Update .analysis_options to link to blocking bugs

Also, some minor cleanup in activity.dart, though much more is
needed (see https://github.com/flutter/flutter/issues/2668).

packages/flutter/lib/src/services/activity.dart

diff --git a/packages/flutter/lib/src/services/activity.dart b/packages/flutter/lib/src/services/activity.dart
index 6bba0fb..4e5d835 100644
--- a/packages/flutter/lib/src/services/activity.dart
+++ b/packages/flutter/lib/src/services/activity.dart
@@ -11,14 +11,29 @@
 
 export 'package:sky_services/activity/activity.mojom.dart';
 
-/// Dart wrapper around Activity mojo service available in Flutter on Android.
-///
-/// Most clients will want to use these methods instead of the activity service
-/// directly.
+// Dart wrapper around Activity mojo service available in Flutter on Android.
+//
+// Most clients will want to use these methods instead of the activity service
+// directly.
 
-const int NEW_DOCUMENT = 0x00080000;
-const int NEW_TASK = 0x10000000;
-const int MULTIPLE_TASK = 0x08000000;
+// The constants below are from
+// http://developer.android.com/reference/android/content/Intent.html
+
+/// Open a document into a new task rooted at the activity launched by
+/// this Intent.
+/// 
+/// See Android's Intent.FLAG_ACTIVITY_NEW_DOCUMENT.
+const int NEW_DOCUMENT = 0x00080000; // ignore: constant_identifier_names
+
+/// Start a new task on this history stack.
+///
+/// See Android's Intent.FLAG_ACTIVITY_NEW_TASK.
+const int NEW_TASK = 0x10000000; // ignore: constant_identifier_names
+
+/// Create a new task and launch an activity into it.
+///
+/// See Android's Intent.FLAG_ACTIVITY_MULTIPLE_TASK.
+const int MULTIPLE_TASK = 0x08000000; // ignore: constant_identifier_names
 
 ActivityProxy _initActivityProxy() {
   ActivityProxy activity = new ActivityProxy.unbound();

packages/flutter_tools/.analysis_options

diff --git a/packages/flutter_tools/.analysis_options b/packages/flutter_tools/.analysis_options
index 0a56cc4..c773324 100644
--- a/packages/flutter_tools/.analysis_options
+++ b/packages/flutter_tools/.analysis_options
@@ -25,16 +25,16 @@
     # - annotate_overrides # still a lot of work to do before enabling this one
     # - avoid_as # https://github.com/dart-lang/linter/issues/195
     - avoid_init_to_null
-    # - avoid_return_types_on_setters # still a lot of work to do before enabling this one
+    # - avoid_return_types_on_setters # https://github.com/dart-lang/linter/issues/202
     - camel_case_types
-    # - constant_identifier_names # still a lot of work to do before enabling this one
+    # - constant_identifier_names # https://github.com/dart-lang/linter/issues/204 (and 203)
     - empty_constructor_bodies
     - hash_and_equals
-    # - implementation_imports # "// ignore:" isn't working yet
+    # - implementation_imports # https://github.com/dart-lang/linter/issues/203
     - library_names
     - library_prefixes
     - non_constant_identifier_names
-    # - one_member_abstracts # "// ignore:" isn't working yet
+    # - one_member_abstracts # https://github.com/dart-lang/linter/issues/203
     - package_api_docs
     - package_names
     - package_prefixed_library_names
@@ -44,7 +44,7 @@
     - sort_constructors_first
     - sort_unnamed_constructors_first
     - super_goes_last
-    # - type_annotate_public_apis # see always_specify_types, which this is a subset of
+    - type_annotate_public_apis # subset of always_specify_types
     - type_init_formals
     - unnecessary_brace_in_string_interp
     - unnecessary_getters_setters