move flutter user analysis options file (#8091)

* move flutter user analysis options file
* add comments referencing each of the analysis options files

.analysis_options

@@ -7,8 +7,13 @@
 # See the configuration guide for more
 # https://github.com/dart-lang/sdk/tree/master/pkg/analyzer#configuring-the-analyzer
 #
+# There are three similar analysis options files in the flutter repo:
+#   - .analysis_options (this file)
+#   - .analysis_options_repo
+#   - packages/flutter/lib/analysis_options_user.yaml
+#
 # This file contains the analysis options used by Flutter editors, such as Atom.
-# It is very similar to .analysis_options_flutter_analyze;
+# It is very similar to the .analysis_options_repo file in this same directory;
 # the only difference (currently) is the public_member_api_docs option,
 # which triggers too many messages to be used in editors.
 

.analysis_options_repo

@@ -7,6 +7,11 @@
 # See the configuration guide for more
 # https://github.com/dart-lang/sdk/tree/master/pkg/analyzer#configuring-the-analyzer
 #
+# There are three similar analysis options files in the flutter repo:
+#   - .analysis_options
+#   - .analysis_options_repo (this file)
+#   - packages/flutter/lib/analysis_options_user.yaml
+#
 # This file contains the analysis options used by 'flutter analyze' when analyzing
 # the flutter repository. It is very similar to .analysis_options;
 # the only difference (currently) is the public_member_api_docs option,

.analysis_options_user → packages/flutter/lib/analysis_options_user.yaml

@@ -7,9 +7,14 @@
 # See the configuration guide for more
 # https://github.com/dart-lang/sdk/tree/master/pkg/analyzer#configuring-the-analyzer
 #
+# There are three similar analysis options files in the flutter repo:
+#   - .analysis_options
+#   - .analysis_options_repo
+#   - packages/flutter/lib/analysis_options_user.yaml (this file)
+#
 # This file contains the analysis options used by "flutter analyze"
-# when analyzing code outside the flutter repository.
-# It isn't named '.analysis_options' because otherwise editors like Atom
+# and the dartanalyzer when analyzing code outside the flutter repository.
+# It isn't named 'analysis_options.yaml' because otherwise editors like Atom
 # would use it when analyzing the flutter tool itself.
 #
 # When editing, make sure you keep /.analysis_options consistent.

packages/flutter_tools/lib/src/commands/analyze_once.dart

@@ -148,7 +148,7 @@ class AnalyzeOnce extends AnalyzeBase {
     options.packageMap = packages;
     options.analysisOptionsFile = flutterRepo
         ? path.join(Cache.flutterRoot, '.analysis_options_repo')
-        : path.join(Cache.flutterRoot, '.analysis_options_user');
+        : path.join(Cache.flutterRoot, 'packages', 'flutter', 'lib', 'analysis_options_user.yaml');
     AnalysisDriver analyzer = new AnalysisDriver(options);
 
     // TODO(pq): consider error handling