[components] Don't use bare package URLs.

We already don't use bare package URLs, but the package build rules
still request support for it. So we just adjust the test rules.

However, we still used to use a bare package URL for context engine
in its integration test, even though the intergration test component
was not flagged thus. Adjusting that too.

Collateral cleanup:
* const

TESTED=/pkgfs/packages/modular_tests/0/test/run_modular_tests.sh

CF-478 #done

Change-Id: I2d7adfc1cad4f239f7d895f82e7436112a9c6fc6
diff --git a/bin/context_engine/BUILD.gn b/bin/context_engine/BUILD.gn
index 2920653..93cc674 100644
--- a/bin/context_engine/BUILD.gn
+++ b/bin/context_engine/BUILD.gn
@@ -6,8 +6,6 @@
 import("//peridot/build/tests_package.gni")
 
 executable_package("context_engine") {
-  deprecated_bare_package_url = "//build"
-
   meta = [
     {
       path = "meta/context_engine.cmx"
diff --git a/bin/context_engine/context_engine_main.cc b/bin/context_engine/context_engine_main.cc
index 061863c..279aaef 100644
--- a/bin/context_engine/context_engine_main.cc
+++ b/bin/context_engine/context_engine_main.cc
@@ -16,7 +16,7 @@
 
 class ContextEngineApp {
  public:
-  ContextEngineApp(component::StartupContext* context) {
+  ContextEngineApp(component::StartupContext* const context) {
     auto component_context =
         context
             ->ConnectToEnvironmentService<fuchsia::modular::ComponentContext>();
diff --git a/tests/maxwell_integration/context_engine_test_base.cc b/tests/maxwell_integration/context_engine_test_base.cc
index 654d461..2e5600f 100644
--- a/tests/maxwell_integration/context_engine_test_base.cc
+++ b/tests/maxwell_integration/context_engine_test_base.cc
@@ -6,11 +6,18 @@
 
 #include "peridot/lib/testing/wait_until_idle.h"
 
+namespace {
+
+constexpr char kContextEngineUrl[] =
+    "fuchsia-pkg://fuchsia.com/context_engine#meta/context_engine.cmx";
+
+}
+
 namespace maxwell {
 
 void ContextEngineTestBase::SetUp() {
   context_engine_ =
-      ConnectToService<fuchsia::modular::ContextEngine>("context_engine");
+      ConnectToService<fuchsia::modular::ContextEngine>(kContextEngineUrl);
   context_engine_->GetContextDebug(debug_.NewRequest());
 }