detect flutter and use default analysis options for flutter

pkg/analyzer/lib/src/context/builder.dart

Index: pkg/analyzer/lib/src/context/builder.dart
diff --git a/pkg/analyzer/lib/src/context/builder.dart b/pkg/analyzer/lib/src/context/builder.dart
index 1c9c3c2b8d676612dfc805b0c4249ba38ca35e7b..98e5effaff71de30dbb70cd8291fb9affb69127d 100644
--- a/pkg/analyzer/lib/src/context/builder.dart
+++ b/pkg/analyzer/lib/src/context/builder.dart
@@ -403,9 +403,16 @@ class ContextBuilder {
       }
     } else {
       // Search for the default analysis options
-      // TODO(danrubel) check for flutter and use default flutter options
-      Source source =
-          sourceFactory.forUri('package:dart.analysis_options/default.yaml');
+      Source source;
+      // TODO(danrubel) determine if bazel or gn project depends upon flutter
+      if (workspace.hasFlutterDependency) {
+        source =
+            sourceFactory.forUri('package:flutter/analysis_options_user.yaml');
+      }
+      if (source == null || !source.exists()) {
+        source =
+            sourceFactory.forUri('package:dart.analysis_options/default.yaml');
+      }
       if (source.exists()) {
         try {
           optionMap = optionsProvider.getOptionsFromSource(source);
@@ -734,6 +741,10 @@ class _BasicWorkspace extends Workspace {
     return _packageMap;
   }
 
+  @override
+  // Alternately, we could check the pubspec for "sdk: flutter"

[Brian Wilkerson, 2017/01/30 20:40:47]

Personally, I think checking the package map is better. We don't currently have
support for reading the pubspec.yaml file, while we do have a package map.

[danrubel, 2017/01/30 20:47:11]

Agreed.

+  bool get hasFlutterDependency => packageMap.containsKey('flutter');
+
   Packages get packages {
     _packages ??= _builder.createPackageMap(root);
     return _packages;