[modular][puppetmaster] Migrate story commands to mod_name_transitional

This is part of a soft transition to convert |mod_name| from a vector
to a string.

MF-148 #comment

Test: CQ
Change-Id: Ia25b7b003f210f6eec3f84f9aa8eba24150d935b
diff --git a/peridot/bin/module_resolver/local_module_resolver.cc b/peridot/bin/module_resolver/local_module_resolver.cc
index 0ac049b..1fdd6b4 100644
--- a/peridot/bin/module_resolver/local_module_resolver.cc
+++ b/peridot/bin/module_resolver/local_module_resolver.cc
@@ -262,8 +262,8 @@
 
       using iter = decltype(results->begin());
       response_.results.insert(response_.results.end(),
-                                std::move_iterator<iter>(results->begin()),
-                                std::move_iterator<iter>(results->end()));
+                               std::move_iterator<iter>(results->begin()),
+                               std::move_iterator<iter>(results->end()));
     }
   }
 
@@ -454,8 +454,7 @@
   fuchsia::modular::FindModulesByTypesQuery const query_;
   fuchsia::modular::FindModulesByTypesResponse response_;
   // A cache of the parameter types for each parameter name in |query_|.
-  std::map<std::string, std::vector<std::string>>
-      parameter_types_cache_;
+  std::map<std::string, std::vector<std::string>> parameter_types_cache_;
 
   FXL_DISALLOW_COPY_AND_ASSIGN(FindModulesByTypesCall);
 };
@@ -522,7 +521,7 @@
 
         fuchsia::modular::AddMod add_mod;
         add_mod.intent.handler = manifest.binary;
-        add_mod.mod_name.push_back("root");
+        add_mod.mod_name_transitional = "root";
 
         fuchsia::modular::StoryCommand command;
         command.set_add_mod(std::move(add_mod));
@@ -630,7 +629,9 @@
       }
     }
 
-    if (already_checking_if_sources_are_ready_) return;
+    if (already_checking_if_sources_are_ready_) {
+      return;
+    }
     already_checking_if_sources_are_ready_ = true;
     async::PostDelayedTask(
         async_get_default_dispatcher(),
diff --git a/peridot/bin/sessionctl/session_ctl_app.cc b/peridot/bin/sessionctl/session_ctl_app.cc
index 247b920..8cfb260 100644
--- a/peridot/bin/sessionctl/session_ctl_app.cc
+++ b/peridot/bin/sessionctl/session_ctl_app.cc
@@ -209,7 +209,7 @@
     const std::string& mod_name) {
   fuchsia::modular::StoryCommand command;
   fuchsia::modular::FocusMod focus_mod;
-  focus_mod.mod_name.push_back(mod_name);
+  focus_mod.mod_name_transitional = mod_name;
   command.set_focus_mod(std::move(focus_mod));
   return command;
 }
@@ -225,7 +225,7 @@
   // Add command to add or update the mod (it will be updated if the mod_name
   // already exists in the story).
   fuchsia::modular::AddMod add_mod;
-  add_mod.mod_name.push_back(mod_name);
+  add_mod.mod_name_transitional = mod_name;
   intent.Clone(&add_mod.intent);
   // TODO(MI4-953): Sessionctl takes in inital intent and other fields.
 
@@ -241,7 +241,7 @@
   fuchsia::modular::StoryCommand command;
 
   fuchsia::modular::RemoveMod remove_mod;
-  remove_mod.mod_name.push_back(mod_name);
+  remove_mod.mod_name_transitional = mod_name;
   command.set_remove_mod(std::move(remove_mod));
   commands.push_back(std::move(command));
   return commands;
diff --git a/peridot/bin/sessionctl/session_ctl_app_unittest.cc b/peridot/bin/sessionctl/session_ctl_app_unittest.cc
index a445d7a..8c6dea8 100644
--- a/peridot/bin/sessionctl/session_ctl_app_unittest.cc
+++ b/peridot/bin/sessionctl/session_ctl_app_unittest.cc
@@ -95,8 +95,9 @@
   auto story_data = GetStoryData("mod_url");
   ASSERT_TRUE(story_data);
   EXPECT_EQ("mod_url", story_data->story_name);
-  EXPECT_EQ("mod_url",
-            test_executor_.last_commands().at(0).add_mod().mod_name.at(0));
+  EXPECT_EQ(
+      "mod_url",
+      test_executor_.last_commands().at(0).add_mod().mod_name_transitional);
   EXPECT_EQ("fuchsia-pkg://fuchsia.com/mod_url#meta/mod_url.cmx",
             test_executor_.last_commands().at(0).add_mod().intent.handler);
   EXPECT_EQ(1, test_executor_.execute_count());
@@ -115,8 +116,9 @@
   auto story_data = GetStoryData("www.google.com");
   ASSERT_TRUE(story_data);
   EXPECT_EQ("www.google.com", story_data->story_name);
-  EXPECT_EQ("www.google.com",
-            test_executor_.last_commands().at(0).add_mod().mod_name.at(0));
+  EXPECT_EQ(
+      "www.google.com",
+      test_executor_.last_commands().at(0).add_mod().mod_name_transitional);
   EXPECT_EQ("https://www.google.com",
             test_executor_.last_commands().at(0).add_mod().intent.handler);
   EXPECT_EQ(1, test_executor_.execute_count());
@@ -136,8 +138,9 @@
   auto story_data = GetStoryData("mod_url");
   ASSERT_TRUE(story_data);
   EXPECT_EQ("mod_url", story_data->story_name);
-  EXPECT_EQ("mod_url",
-            test_executor_.last_commands().at(0).add_mod().mod_name.at(0));
+  EXPECT_EQ(
+      "mod_url",
+      test_executor_.last_commands().at(0).add_mod().mod_name_transitional);
   EXPECT_EQ("foobar-pkg://mod_url?q=bad+wolf",
             test_executor_.last_commands().at(0).add_mod().intent.handler);
   EXPECT_EQ(1, test_executor_.execute_count());
@@ -158,7 +161,9 @@
   auto story_data = GetStoryData(story_name);
   ASSERT_TRUE(story_data);
   EXPECT_EQ(story_name, story_data->story_name);
-  EXPECT_EQ("m", test_executor_.last_commands().at(0).add_mod().mod_name.at(0));
+  EXPECT_EQ(
+      "m",
+      test_executor_.last_commands().at(0).add_mod().mod_name_transitional);
   EXPECT_EQ("fuchsia-pkg://fuchsia.com/mod_url#meta/mod_url.cmx",
             test_executor_.last_commands().at(0).add_mod().intent.handler);
   EXPECT_EQ(1, test_executor_.execute_count());
@@ -197,8 +202,9 @@
   auto story_data = GetStoryData(mod);
   ASSERT_TRUE(story_data);
   EXPECT_EQ(mod, story_data->story_name);
-  EXPECT_EQ(mod,
-            test_executor_.last_commands().at(0).remove_mod().mod_name.at(0));
+  EXPECT_EQ(
+      mod,
+      test_executor_.last_commands().at(0).remove_mod().mod_name_transitional);
   EXPECT_EQ(2, test_executor_.execute_count());
 }
 
@@ -225,8 +231,9 @@
   auto story_data = GetStoryData(story_name);
   ASSERT_TRUE(story_data);
   EXPECT_EQ(story_name, story_data->story_name);
-  EXPECT_EQ(mod_name,
-            test_executor_.last_commands().at(0).remove_mod().mod_name.at(0));
+  EXPECT_EQ(
+      mod_name,
+      test_executor_.last_commands().at(0).remove_mod().mod_name_transitional);
   EXPECT_EQ(2, test_executor_.execute_count());
 }
 
diff --git a/peridot/bin/sessionmgr/dev_session_shell.cc b/peridot/bin/sessionmgr/dev_session_shell.cc
index 8e60acd..6895fa1 100644
--- a/peridot/bin/sessionmgr/dev_session_shell.cc
+++ b/peridot/bin/sessionmgr/dev_session_shell.cc
@@ -122,7 +122,7 @@
 
     std::vector<fuchsia::modular::StoryCommand> commands;
     fuchsia::modular::AddMod add_mod;
-    add_mod.mod_name.push_back("root");
+    add_mod.mod_name_transitional = "root";
     add_mod.intent.handler = settings_.root_module;
     add_mod.intent.action = "action";
     add_mod.intent.parameters = CreateIntentParameters();
@@ -207,7 +207,7 @@
   // |SessionShell|
   void AttachView(fuchsia::modular::ViewIdentifier view_id,
                   fidl::InterfaceHandle<fuchsia::ui::viewsv1token::ViewOwner>
-                  view_owner) override {
+                      view_owner) override {
     FXL_LOG(INFO) << "DevSessionShell AttachView(): " << view_id.story_id;
     view_->ConnectView(std::move(view_owner));
   }
@@ -228,8 +228,7 @@
   void OnModuleAdded(fuchsia::modular::ModuleData /*module_data*/) override {}
 
   // |fuchsia::modular::StoryWatcher|
-  void OnModuleFocused(
-      std::vector<std::string> /*module_path*/) override {}
+  void OnModuleFocused(std::vector<std::string> /*module_path*/) override {}
 
   // |fuchsia::modular::NextListener|
   void OnNextResults(
diff --git a/peridot/bin/sessionmgr/puppet_master/command_runners/add_mod_command_runner_unittest.cc b/peridot/bin/sessionmgr/puppet_master/command_runners/add_mod_command_runner_unittest.cc
index b41aba5..b2d0ded 100644
--- a/peridot/bin/sessionmgr/puppet_master/command_runners/add_mod_command_runner_unittest.cc
+++ b/peridot/bin/sessionmgr/puppet_master/command_runners/add_mod_command_runner_unittest.cc
@@ -132,7 +132,6 @@
       const std::string& mod_name, const std::string& parent_mod_name,
       float surface_emphasis, const fuchsia::modular::Intent& intent) {
     fuchsia::modular::AddMod add_mod;
-    add_mod.mod_name = {mod_name};
     add_mod.mod_name_transitional = mod_name;
     if (!parent_mod_name.empty()) {
       add_mod.surface_parent_mod_name.reset({parent_mod_name});
diff --git a/peridot/bin/sessionmgr/puppet_master/dispatch_story_command_executor_unittest.cc b/peridot/bin/sessionmgr/puppet_master/dispatch_story_command_executor_unittest.cc
index bd4182a..f0760b7 100644
--- a/peridot/bin/sessionmgr/puppet_master/dispatch_story_command_executor_unittest.cc
+++ b/peridot/bin/sessionmgr/puppet_master/dispatch_story_command_executor_unittest.cc
@@ -165,14 +165,14 @@
   AddCommandRunner(
       fuchsia::modular::StoryCommand::Tag::kAddMod,
       [&](fidl::StringPtr story_id, fuchsia::modular::StoryCommand command) {
-        names.push_back(command.add_mod().mod_name.at(0));
+        names.push_back(command.add_mod().mod_name_transitional);
         return fuchsia::modular::ExecuteStatus::OK;
       },
       true /* delay_done */);
   AddCommandRunner(
       fuchsia::modular::StoryCommand::Tag::kRemoveMod,
       [&](fidl::StringPtr story_id, fuchsia::modular::StoryCommand command) {
-        names.push_back(command.remove_mod().mod_name.at(0));
+        names.push_back(command.remove_mod().mod_name_transitional);
         return fuchsia::modular::ExecuteStatus::OK;
       });
 
@@ -181,10 +181,10 @@
   std::vector<fuchsia::modular::StoryCommand> commands;
   commands.resize(2);
   fuchsia::modular::AddMod add_mod;
-  add_mod.mod_name.push_back("one");
+  add_mod.mod_name_transitional = "one";
   commands[0].set_add_mod(std::move(add_mod));
   fuchsia::modular::RemoveMod remove_mod;
-  remove_mod.mod_name.push_back("two");
+  remove_mod.mod_name_transitional = "two";
   commands[1].set_remove_mod(std::move(remove_mod));
 
   bool done{false};
diff --git a/peridot/bin/sessionmgr/puppet_master/puppet_master_impl_unittest.cc b/peridot/bin/sessionmgr/puppet_master/puppet_master_impl_unittest.cc
index bd97653..56351d1 100644
--- a/peridot/bin/sessionmgr/puppet_master/puppet_master_impl_unittest.cc
+++ b/peridot/bin/sessionmgr/puppet_master/puppet_master_impl_unittest.cc
@@ -16,7 +16,7 @@
 fuchsia::modular::StoryCommand MakeRemoveModCommand(std::string mod_name) {
   fuchsia::modular::StoryCommand command;
   fuchsia::modular::RemoveMod remove_mod;
-  remove_mod.mod_name.push_back(mod_name);
+  remove_mod.mod_name_transitional = mod_name;
   command.set_remove_mod(std::move(remove_mod));
   return command;
 }
@@ -77,11 +77,11 @@
   EXPECT_EQ("foo", executor_.last_story_id());
   ASSERT_EQ(3u, executor_.last_commands().size());
   EXPECT_EQ("one",
-            executor_.last_commands().at(0).remove_mod().mod_name.at(0));
+            executor_.last_commands().at(0).remove_mod().mod_name_transitional);
   EXPECT_EQ("two",
-            executor_.last_commands().at(1).remove_mod().mod_name.at(0));
+            executor_.last_commands().at(1).remove_mod().mod_name_transitional);
   EXPECT_EQ("three",
-            executor_.last_commands().at(2).remove_mod().mod_name.at(0));
+            executor_.last_commands().at(2).remove_mod().mod_name_transitional);
 }
 
 TEST_F(PuppetMasterTest, CommandsAreSentToExecutor_IfWeCloseStoryChannel) {
@@ -101,9 +101,8 @@
   // Instruct our test executor to return an OK status.
   executor_.SetExecuteReturnResult(fuchsia::modular::ExecuteStatus::OK,
                                    nullptr);
-  story->Execute([&](fuchsia::modular::ExecuteResult r) {
-    callback_called = true;
-  });
+  story->Execute(
+      [&](fuchsia::modular::ExecuteResult r) { callback_called = true; });
   story.Unbind();
   RunLoopUntil([&]() { return executor_.execute_count() > 0; });
   EXPECT_FALSE(callback_called);
@@ -164,7 +163,7 @@
   auto story1_id = executor_.last_story_id();
   ASSERT_EQ(1u, executor_.last_commands().size());
   EXPECT_EQ("one",
-            executor_.last_commands().at(0).remove_mod().mod_name.at(0));
+            executor_.last_commands().at(0).remove_mod().mod_name_transitional);
 
   executor_.SetExecuteReturnResult(fuchsia::modular::ExecuteStatus::OK,
                                    nullptr);
@@ -178,7 +177,7 @@
   auto story2_id = executor_.last_story_id();
   ASSERT_EQ(1u, executor_.last_commands().size());
   EXPECT_EQ("two",
-            executor_.last_commands().at(0).remove_mod().mod_name.at(0));
+            executor_.last_commands().at(0).remove_mod().mod_name_transitional);
 
   // The two IDs should be different, because we gave the two stories different
   // names.
@@ -215,7 +214,7 @@
   auto story_id = executor_.last_story_id();
   ASSERT_EQ(1u, executor_.last_commands().size());
   EXPECT_EQ("one",
-            executor_.last_commands().at(0).remove_mod().mod_name.at(0));
+            executor_.last_commands().at(0).remove_mod().mod_name_transitional);
 
   executor_.SetExecuteReturnResult(fuchsia::modular::ExecuteStatus::OK,
                                    nullptr);
@@ -229,7 +228,7 @@
   EXPECT_EQ(story_id, executor_.last_story_id());
   ASSERT_EQ(1u, executor_.last_commands().size());
   EXPECT_EQ("two",
-            executor_.last_commands().at(0).remove_mod().mod_name.at(0));
+            executor_.last_commands().at(0).remove_mod().mod_name_transitional);
 }
 
 TEST_F(PuppetMasterTest, CreateStoryWithOptions) {
diff --git a/peridot/bin/sessionmgr/puppet_master/story_command_executor_unittest.cc b/peridot/bin/sessionmgr/puppet_master/story_command_executor_unittest.cc
index ca81f73..50809a1 100644
--- a/peridot/bin/sessionmgr/puppet_master/story_command_executor_unittest.cc
+++ b/peridot/bin/sessionmgr/puppet_master/story_command_executor_unittest.cc
@@ -46,7 +46,7 @@
 StoryCommand MakeRemoveModCommand(std::string mod_name) {
   StoryCommand command;
   fuchsia::modular::RemoveMod remove_mod;
-  remove_mod.mod_name.push_back(mod_name);
+  remove_mod.mod_name_transitional = mod_name;
   command.set_remove_mod(std::move(remove_mod));
   return command;
 }
diff --git a/peridot/bin/suggestion_engine/suggestion_engine_impl_unittest.cc b/peridot/bin/suggestion_engine/suggestion_engine_impl_unittest.cc
index e474cab..c96eb86 100644
--- a/peridot/bin/suggestion_engine/suggestion_engine_impl_unittest.cc
+++ b/peridot/bin/suggestion_engine/suggestion_engine_impl_unittest.cc
@@ -165,7 +165,7 @@
     fuchsia::modular::Intent intent;
     intent.handler = mod_url;
     fuchsia::modular::AddMod add_mod;
-    add_mod.mod_name.push_back(mod_name);
+    add_mod.mod_name_transitional = mod_name;
     add_mod.intent = std::move(intent);
     if (!parent_mod.empty()) {
       add_mod.surface_parent_mod_name.push_back(parent_mod);
@@ -188,7 +188,7 @@
   void AddFocusModuleAction(fuchsia::modular::Proposal* proposal,
                             const std::string& mod_name) {
     fuchsia::modular::FocusMod focus_mod;
-    focus_mod.mod_name.push_back(mod_name);
+    focus_mod.mod_name_transitional = mod_name;
     fuchsia::modular::StoryCommand command;
     command.set_focus_mod(std::move(focus_mod));
     proposal->on_selected.push_back(std::move(command));
@@ -329,8 +329,8 @@
   ASSERT_TRUE(commands.at(0).is_add_mod());
 
   auto& command = commands.at(0).add_mod();
-  ASSERT_EQ(1u, command.mod_name.size());
-  EXPECT_EQ("mod_name", command.mod_name.at(0));
+  ASSERT_FALSE(command.mod_name_transitional.is_null());
+  EXPECT_EQ("mod_name", command.mod_name_transitional.get());
   EXPECT_EQ("mod_url", command.intent.handler);
   EXPECT_EQ(fuchsia::modular::SurfaceArrangement::ONTOP,
             command.surface_relation.arrangement);
@@ -388,8 +388,8 @@
   ASSERT_TRUE(commands.at(0).is_add_mod());
 
   auto& command = commands.at(0).add_mod();
-  ASSERT_EQ(1u, command.mod_name.size());
-  EXPECT_EQ("mod_name", command.mod_name.at(0));
+  ASSERT_FALSE(command.mod_name_transitional.is_null());
+  EXPECT_EQ("mod_name", command.mod_name_transitional.get());
   EXPECT_EQ("mod_url", command.intent.handler);
   EXPECT_EQ(fuchsia::modular::SurfaceArrangement::COPRESENT,
             command.surface_relation.arrangement);
@@ -520,16 +520,16 @@
   EXPECT_TRUE(commands.at(3).is_set_link_value());
 
   auto& add_mod = commands.at(0).add_mod();
-  ASSERT_EQ(1u, add_mod.mod_name.size());
-  EXPECT_EQ("mod_name", add_mod.mod_name.at(0));
+  ASSERT_FALSE(add_mod.mod_name_transitional.is_null());
+  EXPECT_EQ("mod_name", add_mod.mod_name_transitional.get());
   EXPECT_EQ("mod_url", add_mod.intent.handler);
 
   auto& set_focus_state = commands.at(1).set_focus_state();
   EXPECT_TRUE(set_focus_state.focused);
 
   auto& focus_mod = commands.at(2).focus_mod();
-  ASSERT_EQ(1u, focus_mod.mod_name.size());
-  EXPECT_EQ("mod_name", focus_mod.mod_name.at(0));
+  ASSERT_FALSE(focus_mod.mod_name_transitional.is_null());
+  EXPECT_EQ("mod_name", focus_mod.mod_name_transitional.get());
 
   auto& set_link_value = commands.at(3).set_link_value();
   ASSERT_EQ(1u, set_link_value.path.module_path.size());
@@ -587,8 +587,8 @@
   ASSERT_EQ(1u, commands.size());
   EXPECT_TRUE(commands.at(0).is_focus_mod());
   auto& focus_mod = commands.at(0).focus_mod();
-  ASSERT_EQ(1u, focus_mod.mod_name.size());
-  EXPECT_EQ("mod_name", focus_mod.mod_name.at(0));
+  ASSERT_FALSE(focus_mod.mod_name_transitional.is_null());
+  EXPECT_EQ("mod_name", focus_mod.mod_name_transitional.get());
 
   // Ensure a regular story was created when we executed the proposal.
   bool done{};
@@ -843,8 +843,8 @@
   auto& commands = test_executor_.last_commands();
   ASSERT_EQ(1u, commands.size());
   auto& focus_mod = commands.at(0).focus_mod();
-  ASSERT_EQ(1u, focus_mod.mod_name.size());
-  EXPECT_EQ("mod_name", focus_mod.mod_name.at(0));
+  ASSERT_FALSE(focus_mod.mod_name_transitional.is_null());
+  EXPECT_EQ("mod_name", focus_mod.mod_name_transitional.get());
 
   // Ensure a regular story was created when we executed the proposal.
   bool done{};
diff --git a/peridot/tests/benchmarks/story/modular_benchmark_story_session_shell.cc b/peridot/tests/benchmarks/story/modular_benchmark_story_session_shell.cc
index 1e249a0..638dff9 100644
--- a/peridot/tests/benchmarks/story/modular_benchmark_story_session_shell.cc
+++ b/peridot/tests/benchmarks/story/modular_benchmark_story_session_shell.cc
@@ -45,7 +45,8 @@
 
     module_url = command_line.GetOptionValueWithDefault(
         "module_url",
-        "fuchsia-pkg://fuchsia.com/modular_benchmark_story_module#meta/modular_benchmark_story_module.cmx");
+        "fuchsia-pkg://fuchsia.com/modular_benchmark_story_module#meta/"
+        "modular_benchmark_story_module.cmx");
   }
 
   int story_count{0};
@@ -182,12 +183,13 @@
   void StoryCreate() {
     FXL_LOG(INFO) << "StoryCreate()";
     TRACE_ASYNC_BEGIN("benchmark", "story/create", 0);
-    std::string story_name = std::string(kStoryNamePrefix) + std::to_string(story_count_);
+    std::string story_name =
+        std::string(kStoryNamePrefix) + std::to_string(story_count_);
     puppet_master_->ControlStory(story_name, story_puppet_master_.NewRequest());
 
     std::vector<fuchsia::modular::StoryCommand> commands;
     fuchsia::modular::AddMod add_mod;
-    add_mod.mod_name.push_back("root");
+    add_mod.mod_name_transitional = "root";
     add_mod.intent.handler = settings_.module_url;
     add_mod.intent.action = "action";
 
diff --git a/peridot/tests/embed_shell/embed_shell_test_session_shell.cc b/peridot/tests/embed_shell/embed_shell_test_session_shell.cc
index c5a2c4c..5830650 100644
--- a/peridot/tests/embed_shell/embed_shell_test_session_shell.cc
+++ b/peridot/tests/embed_shell/embed_shell_test_session_shell.cc
@@ -44,7 +44,7 @@
     puppet_master_->ControlStory(kStoryName, story_puppet_master_.NewRequest());
 
     fuchsia::modular::AddMod add_mod;
-    add_mod.mod_name.push_back("root");
+    add_mod.mod_name_transitional = "root";
     add_mod.intent.handler = kParentModuleUrl;
     add_mod.intent.action = kParentModuleAction;
     add_mod.intent.parameters =
diff --git a/peridot/tests/last_focus_time/last_focus_time_test_session_shell.cc b/peridot/tests/last_focus_time/last_focus_time_test_session_shell.cc
index 849df8e..14812fa 100644
--- a/peridot/tests/last_focus_time/last_focus_time_test_session_shell.cc
+++ b/peridot/tests/last_focus_time/last_focus_time_test_session_shell.cc
@@ -114,8 +114,7 @@
   void OnModuleAdded(fuchsia::modular::ModuleData /*module_data*/) override {}
 
   // |fuchsia::modular::StoryWatcher|
-  void OnModuleFocused(
-      std::vector<std::string> /*module_path*/) override {}
+  void OnModuleFocused(std::vector<std::string> /*module_path*/) override {}
 
   fidl::Binding<fuchsia::modular::StoryWatcher> binding_;
   std::function<void()> continue_;
@@ -174,7 +173,7 @@
     puppet_master_->ControlStory(kStoryName, story_puppet_master_.NewRequest());
 
     fuchsia::modular::AddMod add_mod;
-    add_mod.mod_name.push_back("mod1");
+    add_mod.mod_name_transitional = "mod1";
     add_mod.intent.handler = kCommonNullModule;
     add_mod.intent.action = kCommonNullAction;
 
diff --git a/peridot/tests/link_context_entities/link_context_entities_test_session_shell.cc b/peridot/tests/link_context_entities/link_context_entities_test_session_shell.cc
index 918d37f..82d7650 100644
--- a/peridot/tests/link_context_entities/link_context_entities_test_session_shell.cc
+++ b/peridot/tests/link_context_entities/link_context_entities_test_session_shell.cc
@@ -113,7 +113,7 @@
 
     std::vector<fuchsia::modular::StoryCommand> commands;
     fuchsia::modular::AddMod add_mod;
-    add_mod.mod_name.push_back("root");
+    add_mod.mod_name_transitional = "root";
     add_mod.intent.handler = kModuleUrl;
     add_mod.intent.action = kModuleAction;
 
@@ -218,9 +218,7 @@
     }
   }
 
-  void Logout() {
-    Signal(modular::testing::kTestShutdown);
-  }
+  void Logout() { Signal(modular::testing::kTestShutdown); }
 
   fuchsia::modular::PuppetMasterPtr puppet_master_;
   fuchsia::modular::StoryPuppetMasterPtr story_puppet_master_;
diff --git a/peridot/tests/maxwell_integration/suggestion_engine_test.cc b/peridot/tests/maxwell_integration/suggestion_engine_test.cc
index 278742c..c243fa7 100644
--- a/peridot/tests/maxwell_integration/suggestion_engine_test.cc
+++ b/peridot/tests/maxwell_integration/suggestion_engine_test.cc
@@ -65,7 +65,7 @@
   virtual ~Proposinator() = default;
 
   void Propose(const std::string& id,
-               std::vector<fuchsia::modular::StoryCommand> commands ={}) {
+               std::vector<fuchsia::modular::StoryCommand> commands = {}) {
     Propose(id, id, fuchsia::modular::AnnoyanceType::NONE, std::move(commands));
   }
 
@@ -135,7 +135,7 @@
       const std::string& id, const std::string& headline,
       fuchsia::modular::AnnoyanceType annoyance =
           fuchsia::modular::AnnoyanceType::NONE,
-      std::vector<fuchsia::modular::StoryCommand> commands ={}) {
+      std::vector<fuchsia::modular::StoryCommand> commands = {}) {
     query_proposals_.push_back(
         CreateProposal(id, headline, std::move(commands), annoyance));
   }
@@ -206,8 +206,9 @@
   void SetUp() override {
     ContextEngineTestBase::SetUp();
 
-    component::Services suggestion_services =
-        StartServices("fuchsia-pkg://fuchsia.com/suggestion_engine#meta/suggestion_engine.cmx");
+    component::Services suggestion_services = StartServices(
+        "fuchsia-pkg://fuchsia.com/suggestion_engine#meta/"
+        "suggestion_engine.cmx");
     suggestion_engine_ =
         suggestion_services
             .ConnectToService<fuchsia::modular::SuggestionEngine>();
@@ -877,7 +878,7 @@
   fuchsia::modular::Intent intent;
   intent.handler = "foo://bar";
   fuchsia::modular::AddMod add_mod;
-  add_mod.mod_name.push_back("foo");
+  add_mod.mod_name_transitional = "foo";
   add_mod.intent = std::move(intent);
 
   fuchsia::modular::StoryCommand command;
@@ -908,7 +909,7 @@
   intent.handler = "foo://bar";
   fuchsia::modular::AddMod add_mod;
   add_mod.intent = std::move(intent);
-  add_mod.mod_name.push_back("foo");
+  add_mod.mod_name_transitional = "foo";
 
   fuchsia::modular::StoryCommand command;
   command.set_add_mod(std::move(add_mod));
diff --git a/peridot/tests/module_context/module_context_test_session_shell.cc b/peridot/tests/module_context/module_context_test_session_shell.cc
index 17f2238..89e6c58 100644
--- a/peridot/tests/module_context/module_context_test_session_shell.cc
+++ b/peridot/tests/module_context/module_context_test_session_shell.cc
@@ -35,19 +35,18 @@
  public:
   StoryActivityWatcherImpl()
       : binding_(this),
-        on_notify_(
-            [](std::string,
-               std::vector<fuchsia::modular::OngoingActivityType>) {}) {}
+        on_notify_([](std::string,
+                      std::vector<fuchsia::modular::OngoingActivityType>) {}) {}
   ~StoryActivityWatcherImpl() override = default;
 
   void Watch(fuchsia::modular::StoryProvider* const story_provider) {
     story_provider->WatchActivity(binding_.NewBinding());
   }
 
-  void OnNotify(std::function<
-                void(std::string,
-                     std::vector<fuchsia::modular::OngoingActivityType>)>
-                    on_notify) {
+  void OnNotify(
+      std::function<void(std::string,
+                         std::vector<fuchsia::modular::OngoingActivityType>)>
+          on_notify) {
     on_notify_ = std::move(on_notify);
   }
 
@@ -55,8 +54,7 @@
   // |fuchsia::modular::StoryActivityWatcher|
   void OnStoryActivityChange(
       std::string story_id,
-      std::vector<fuchsia::modular::OngoingActivityType> activities)
-      override {
+      std::vector<fuchsia::modular::OngoingActivityType> activities) override {
     on_notify_(std::move(story_id), std::move(activities));
   }
 
@@ -87,7 +85,7 @@
     std::vector<fuchsia::modular::StoryCommand> commands;
     {
       fuchsia::modular::AddMod add_mod;
-      add_mod.mod_name.push_back(kFirstModuleName);
+      add_mod.mod_name_transitional = kFirstModuleName;
       add_mod.intent = IntentWithParameterString(kFirstModuleName);
 
       fuchsia::modular::StoryCommand command;
@@ -96,7 +94,7 @@
     }
     {
       fuchsia::modular::AddMod add_mod;
-      add_mod.mod_name.push_back(kSecondModuleName);
+      add_mod.mod_name_transitional = kSecondModuleName;
       add_mod.intent = IntentWithParameterString(kSecondModuleName);
 
       fuchsia::modular::StoryCommand command;
@@ -108,7 +106,7 @@
       intent.handler = kEntityModuleUrl;
       intent.action = kEntityIntentAction;
       fuchsia::modular::AddMod add_mod;
-      add_mod.mod_name.push_back("entity_module");
+      add_mod.mod_name_transitional = "entity_module";
       add_mod.intent = std::move(intent);
       add_mod.surface_parent_mod_name.resize(0);
 
@@ -148,9 +146,8 @@
   void PerformWatchActivity() {
     story_activity_watcher_.Watch(story_provider());
     story_activity_watcher_.OnNotify(
-        [this](
-            std::string story_id,
-            std::vector<fuchsia::modular::OngoingActivityType> activities) {
+        [this](std::string story_id,
+               std::vector<fuchsia::modular::OngoingActivityType> activities) {
           if (story_id == kStoryName && activities.empty()) {
             on_watch_ongoing_activities_dispatched.Pass();
           }
@@ -165,12 +162,10 @@
   void PerformFirstModuleStartActivity() {
     Signal(kFirstModuleCallStartActivity);
     story_activity_watcher_.OnNotify(
-        [this](
-            std::string story_id,
-            std::vector<fuchsia::modular::OngoingActivityType> activities) {
+        [this](std::string story_id,
+               std::vector<fuchsia::modular::OngoingActivityType> activities) {
           if (story_id == kStoryName && activities.size() == 1 &&
-              activities[0] ==
-                  fuchsia::modular::OngoingActivityType::VIDEO) {
+              activities[0] == fuchsia::modular::OngoingActivityType::VIDEO) {
             on_start_ongoing_activity_dispatched.Pass();
           }
           PerformSecondModuleStartActivity();
@@ -184,14 +179,11 @@
   void PerformSecondModuleStartActivity() {
     Signal(kSecondModuleCallStartActivity);
     story_activity_watcher_.OnNotify(
-        [this](
-            std::string story_id,
-            std::vector<fuchsia::modular::OngoingActivityType> activities) {
+        [this](std::string story_id,
+               std::vector<fuchsia::modular::OngoingActivityType> activities) {
           if (story_id == kStoryName && activities.size() == 2 &&
-              activities[0] ==
-                  fuchsia::modular::OngoingActivityType::VIDEO &&
-              activities[1] ==
-                  fuchsia::modular::OngoingActivityType::VIDEO) {
+              activities[0] == fuchsia::modular::OngoingActivityType::VIDEO &&
+              activities[1] == fuchsia::modular::OngoingActivityType::VIDEO) {
             on_start_all_ongoing_activities_dispatched.Pass();
           }
           PerformSecondModuleStopActivity();
@@ -205,12 +197,10 @@
   void PerformSecondModuleStopActivity() {
     Signal(kSecondModuleCallStopActivity);
     story_activity_watcher_.OnNotify(
-        [this](
-            std::string story_id,
-            std::vector<fuchsia::modular::OngoingActivityType> activities) {
+        [this](std::string story_id,
+               std::vector<fuchsia::modular::OngoingActivityType> activities) {
           if (story_id == kStoryName && activities.size() == 1 &&
-              activities[0] ==
-                  fuchsia::modular::OngoingActivityType::VIDEO) {
+              activities[0] == fuchsia::modular::OngoingActivityType::VIDEO) {
             on_stop_remaining_ongoing_activities_dispatched.Pass();
           }
           TestModuleCreatingEntity();
@@ -224,7 +214,7 @@
         intent.handler = kEntityModuleUrl;
         intent.action = kEntityIntentAction;
         fuchsia::modular::RemoveMod remove_mod;
-        remove_mod.mod_name.push_back("entity_module");
+        remove_mod.mod_name_transitional = "entity_module";
 
         std::vector<fuchsia::modular::StoryCommand> commands;
         fuchsia::modular::StoryCommand command;
@@ -264,9 +254,8 @@
     });
 
     story_activity_watcher_.OnNotify(
-        [this](
-            std::string story_id,
-            std::vector<fuchsia::modular::OngoingActivityType> activities) {
+        [this](std::string story_id,
+               std::vector<fuchsia::modular::OngoingActivityType> activities) {
           if (story_id == kStoryName && activities.empty()) {
             on_done_ongoing_activities_stopped.Pass();
           }
diff --git a/peridot/tests/session_shell/session_shell_test_session_shell.cc b/peridot/tests/session_shell/session_shell_test_session_shell.cc
index 21613c2..aa7a1e3 100644
--- a/peridot/tests/session_shell/session_shell_test_session_shell.cc
+++ b/peridot/tests/session_shell/session_shell_test_session_shell.cc
@@ -263,7 +263,7 @@
     puppet_master_->ControlStory("story1", story_puppet_master_.NewRequest());
 
     fuchsia::modular::AddMod add_mod;
-    add_mod.mod_name.push_back("mod1");
+    add_mod.mod_name_transitional = "mod1";
     add_mod.intent.handler = kCommonActiveModule;
 
     fuchsia::modular::IntentParameter param;
@@ -332,7 +332,7 @@
     puppet_master_->ControlStory("story2", story_puppet_master_.NewRequest());
 
     fuchsia::modular::AddMod add_mod;
-    add_mod.mod_name.push_back("mod1");
+    add_mod.mod_name_transitional = "mod1";
     add_mod.intent.handler = kCommonNullModule;
 
     fuchsia::modular::StoryCommand command;
@@ -541,7 +541,7 @@
     puppet_master_->ControlStory("story4", story_puppet_master_.NewRequest());
 
     fuchsia::modular::AddMod add_mod;
-    add_mod.mod_name.push_back("mod1");
+    add_mod.mod_name_transitional = "mod1";
     add_mod.intent.handler = kCommonNullModule;
 
     fuchsia::modular::StoryCommand command;
@@ -638,7 +638,7 @@
     puppet_master_->ControlStory("story5", story_puppet_master_.NewRequest());
 
     fuchsia::modular::AddMod add_mod;
-    add_mod.mod_name.push_back("mod1");
+    add_mod.mod_name_transitional = "mod1";
     add_mod.intent.handler = kCommonNullModule;
 
     fuchsia::modular::StoryCommand command;
@@ -739,7 +739,7 @@
     puppet_master_->ControlStory("story6", story_puppet_master_.NewRequest());
 
     fuchsia::modular::AddMod add_mod;
-    add_mod.mod_name.push_back("mod1");
+    add_mod.mod_name_transitional = "mod1";
     add_mod.intent.handler = kCommonNullModule;
 
     fuchsia::modular::StoryCommand command;
diff --git a/peridot/tests/story_shell/story_shell_test_session_shell.cc b/peridot/tests/story_shell/story_shell_test_session_shell.cc
index 5395d03..387e98b 100644
--- a/peridot/tests/story_shell/story_shell_test_session_shell.cc
+++ b/peridot/tests/story_shell/story_shell_test_session_shell.cc
@@ -113,7 +113,7 @@
     auto addMod = [&commands](fidl::StringPtr name,
                               std::vector<fidl::StringPtr> parent) {
       fuchsia::modular::AddMod add_mod;
-      add_mod.mod_name.push_back(name);
+      add_mod.mod_name_transitional = name;
       add_mod.intent.action = kCommonNullAction;
       add_mod.intent.handler = kCommonNullModule;
 
@@ -143,7 +143,8 @@
   TestPoint story1_run1_{"Story1 Run1"};
 
   void Story1_Run1() {
-    story_provider()->GetController(kStoryName1, story_controller_.NewRequest());
+    story_provider()->GetController(kStoryName1,
+                                    story_controller_.NewRequest());
 
     // TODO(jphsiao|vardhan): remodel this |proceed_after_6| style of
     // continuation to use Futures instead.
@@ -198,7 +199,7 @@
     auto addMod = [&commands](fidl::StringPtr name,
                               std::vector<fidl::StringPtr> parent) {
       fuchsia::modular::AddMod add_mod;
-      add_mod.mod_name.push_back(name);
+      add_mod.mod_name_transitional = name;
       add_mod.intent.action = kCommonNullAction;
       add_mod.intent.handler = kCommonNullModule;
 
@@ -239,7 +240,8 @@
     Get("root:one:two manifest", proceed_after_5);
     Get("root:one:two ordering", proceed_after_5);
 
-    story_provider()->GetController(kStoryName2, story_controller_.NewRequest());
+    story_provider()->GetController(kStoryName2,
+                                    story_controller_.NewRequest());
     story_controller_->RequestStart();
   }
 
diff --git a/peridot/tests/suggestion/suggestion_test_session_shell.cc b/peridot/tests/suggestion/suggestion_test_session_shell.cc
index 1f1ec76..56678de 100644
--- a/peridot/tests/suggestion/suggestion_test_session_shell.cc
+++ b/peridot/tests/suggestion/suggestion_test_session_shell.cc
@@ -51,7 +51,7 @@
   void CreateStory() {
     std::vector<fuchsia::modular::StoryCommand> commands;
     fuchsia::modular::AddMod add_mod;
-    add_mod.mod_name.push_back("root");
+    add_mod.mod_name_transitional = "root";
     add_mod.intent.action = kSuggestionTestAction;
     add_mod.intent.handler = kSuggestionTestModule;
 
diff --git a/peridot/tests/trigger/trigger_test_session_shell.cc b/peridot/tests/trigger/trigger_test_session_shell.cc
index 9aa7b2c..7dbc548 100644
--- a/peridot/tests/trigger/trigger_test_session_shell.cc
+++ b/peridot/tests/trigger/trigger_test_session_shell.cc
@@ -47,7 +47,7 @@
   void CreateStory() {
     std::vector<fuchsia::modular::StoryCommand> commands;
     fuchsia::modular::AddMod add_mod;
-    add_mod.mod_name.push_back("root");
+    add_mod.mod_name_transitional = "root";
 
     add_mod.intent.action = kModuleAction;
     add_mod.intent.handler = kModuleUrl;