[build][flutter] Use flutter_app polyfill.

Migrate away from //topaz/runtime/flutter_runner/flutter_app.gni.

Bug: 58062
Change-Id: I895f581e4c7e5c698c584ededcfab5b4e10ce67e
Reviewed-on: https://fuchsia-review.googlesource.com/c/experiences/+/445355
Reviewed-by: Ian McKellar <ianloic@google.com>
Reviewed-by: Chase Latta <chaselatta@google.com>
Commit-Queue: Darren Chan <chandarren@google.com>
diff --git a/benchmarks/bin/button_flutter/BUILD.gn b/benchmarks/bin/button_flutter/BUILD.gn
index 39893ca..6d2de6c 100644
--- a/benchmarks/bin/button_flutter/BUILD.gn
+++ b/benchmarks/bin/button_flutter/BUILD.gn
@@ -2,7 +2,7 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-import("//topaz/runtime/flutter_runner/flutter_app.gni")
+import("//build/flutter/flutter_app.gni")
 
 flutter_app("button_flutter") {
   main_dart = "lib/main.dart"
diff --git a/benchmarks/bin/clockface_flutter/BUILD.gn b/benchmarks/bin/clockface_flutter/BUILD.gn
index 2110aed..beba07c 100644
--- a/benchmarks/bin/clockface_flutter/BUILD.gn
+++ b/benchmarks/bin/clockface_flutter/BUILD.gn
@@ -2,7 +2,7 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-import("//topaz/runtime/flutter_runner/flutter_app.gni")
+import("//build/flutter/flutter_app.gni")
 
 flutter_app("clockface-flutter") {
   main_dart = "lib/main.dart"
diff --git a/benchmarks/bin/gamma_flutter/BUILD.gn b/benchmarks/bin/gamma_flutter/BUILD.gn
index 67e81a8..1919891 100644
--- a/benchmarks/bin/gamma_flutter/BUILD.gn
+++ b/benchmarks/bin/gamma_flutter/BUILD.gn
@@ -2,7 +2,7 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-import("//topaz/runtime/flutter_runner/flutter_app.gni")
+import("//build/flutter/flutter_app.gni")
 
 flutter_app("gamma-flutter") {
   main_dart = "lib/main.dart"
diff --git a/benchmarks/bin/scroll_flutter/BUILD.gn b/benchmarks/bin/scroll_flutter/BUILD.gn
index 0def183..7681612 100644
--- a/benchmarks/bin/scroll_flutter/BUILD.gn
+++ b/benchmarks/bin/scroll_flutter/BUILD.gn
@@ -2,7 +2,7 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-import("//topaz/runtime/flutter_runner/flutter_app.gni")
+import("//build/flutter/flutter_app.gni")
 
 flutter_app("scroll-flutter") {
   main_dart = "lib/main.dart"
diff --git a/bin/simple_browser/BUILD.gn b/bin/simple_browser/BUILD.gn
index b9da46b..698425c 100644
--- a/bin/simple_browser/BUILD.gn
+++ b/bin/simple_browser/BUILD.gn
@@ -63,7 +63,7 @@
 
 resource("keyboard-shortcuts") {
   sources = [ "config/keyboard_shortcuts.json" ]
-  outputs = [ "keyboard_shortcuts.json" ]
+  outputs = [ "data/keyboard_shortcuts.json" ]
 }
 
 flutter_component("component") {
diff --git a/bin/simple_browser_internationalization/BUILD.gn b/bin/simple_browser_internationalization/BUILD.gn
index eda7bd3..8fc4fab 100644
--- a/bin/simple_browser_internationalization/BUILD.gn
+++ b/bin/simple_browser_internationalization/BUILD.gn
@@ -3,9 +3,6 @@
 # found in the LICENSE file.
 
 import("//build/dart/dart_library.gni")
-import("//src/modular/build/modular_config/modular_config.gni")
-import("//topaz/runtime/dart/flutter_test.gni")
-import("//topaz/runtime/flutter_runner/flutter_app.gni")
 
 dart_library("internationalization") {
   package_name = "internationalization"
diff --git a/session_shells/ermine/internationalization/BUILD.gn b/session_shells/ermine/internationalization/BUILD.gn
index eda7bd3..8fc4fab 100644
--- a/session_shells/ermine/internationalization/BUILD.gn
+++ b/session_shells/ermine/internationalization/BUILD.gn
@@ -3,9 +3,6 @@
 # found in the LICENSE file.
 
 import("//build/dart/dart_library.gni")
-import("//src/modular/build/modular_config/modular_config.gni")
-import("//topaz/runtime/dart/flutter_test.gni")
-import("//topaz/runtime/flutter_runner/flutter_app.gni")
 
 dart_library("internationalization") {
   package_name = "internationalization"
diff --git a/session_shells/ermine/shell/BUILD.gn b/session_shells/ermine/shell/BUILD.gn
index c01fa7b..ce419cb 100644
--- a/session_shells/ermine/shell/BUILD.gn
+++ b/session_shells/ermine/shell/BUILD.gn
@@ -9,7 +9,7 @@
 import("//build/testing/flutter_driver.gni")
 import("//src/lib/icu/tools/static_icu_data.gni")
 import("//topaz/runtime/dart/flutter_test.gni")
-import("//topaz/runtime/flutter_runner/flutter_app.gni")
+import("//build/flutter/flutter_app.gni")
 
 group("shell") {
   public_deps = [