Use the correct set of options to analyze Flutter packages. (#9758)

This affects the Fuchsia build which will soon run analysis by default.

examples/flutter_gallery/BUILD.gn

@@ -9,6 +9,8 @@ assert(is_fuchsia)
 flutter_app("flutter_gallery") {
   main_dart = "lib/main.dart"
 
+  analysis_options = "//lib/flutter/.analysis_options"
+
   deps = [
     "//lib/flutter/packages/flutter",
   ]

packages/flutter/BUILD.gn

@@ -7,7 +7,7 @@ import("//build/dart/dart_package.gni")
 dart_package("flutter") {
   package_name = "flutter"
 
-  source_dir = "lib"
+  analysis_options = "//lib/flutter/.analysis_options"
 
   deps = [
     "//third_party/dart-pkg/pub/async",

packages/flutter_test/BUILD.gn

@@ -7,7 +7,7 @@ import("//build/dart/dart_package.gni")
 dart_package("flutter_test") {
   package_name = "flutter_test"
 
-  source_dir = "lib"
+  analysis_options = "//lib/flutter/.analysis_options"
 
   deps = [
     "//lib/flutter/packages/flutter",

packages/flutter_tools/BUILD.gn

@@ -8,7 +8,7 @@ import("//build/dart/dart_tool.gni")
 dart_package("flutter_tools") {
   package_name = "flutter_tools"
 
-  source_dir = "lib"
+  analysis_options = "//lib/flutter/.analysis_options"
 
   deps = [
     "//dart/pkg/analyzer",
@@ -42,6 +42,8 @@ dart_package("flutter_tools") {
 dart_tool("fuchsia_builder") {
   main_dart = "bin/fuchsia_builder.dart"
 
+  analysis_options = "//lib/flutter/.analysis_options"
+
   deps = [
     ":flutter_tools",
   ]
@@ -50,6 +52,8 @@ dart_tool("fuchsia_builder") {
 dart_tool("fuchsia_tester") {
   main_dart = "bin/fuchsia_tester.dart"
 
+  analysis_options = "//lib/flutter/.analysis_options"
+
   deps = [
     ":flutter_tools",
   ]