cc: Making BeginFrameSources support multiple BeginFrameObservers.

cc/scheduler/begin_frame_source_unittest.cc

Index: cc/scheduler/begin_frame_source_unittest.cc
diff --git a/cc/scheduler/begin_frame_source_unittest.cc b/cc/scheduler/begin_frame_source_unittest.cc
index 22126bead4504af443d585740c491a68710833a9..edc3268dc30f1ae63c1a3b05857b472ee764410d 100644
--- a/cc/scheduler/begin_frame_source_unittest.cc
+++ b/cc/scheduler/begin_frame_source_unittest.cc
@@ -62,9 +62,9 @@ namespace {
 class MockBeginFrameObserver : public BeginFrameObserver {
  public:
   MOCK_METHOD1(OnBeginFrame, void(const BeginFrameArgs&));
-  MOCK_CONST_METHOD0(LastUsedBeginFrameArgs, const BeginFrameArgs());
+  MOCK_METHOD0(LastUsedBeginFrameArgs, const BeginFrameArgs());
 
-  virtual void AsValueInto(base::trace_event::TracedValue* dict) const {
+  virtual void AsValueInto(base::trace_event::TracedValue* dict) {
     dict->SetString("type", "MockBeginFrameObserver");
     dict->BeginDictionary("last_begin_frame_args");
     LastUsedBeginFrameArgs().AsValueInto(dict);
@@ -231,9 +231,6 @@ TEST(BeginFrameSourceMixInTest, ObserverManipulation) {
   EXPECT_EQ(&obs, source.GetObserver());
 
 #ifndef NDEBUG
-  // Adding an observer when an observer already exists should DCHECK fail.
-  EXPECT_DEATH({ source.AddObserver(&otherObs); }, "");
-
   // Removing wrong observer should DCHECK fail.
   EXPECT_DEATH({ source.RemoveObserver(&otherObs); }, "");
 
@@ -284,7 +281,7 @@ class LoopingBeginFrameObserver : public BeginFrameObserverMixIn {
  public:
   BeginFrameSource* source_;
 
-  void AsValueInto(base::trace_event::TracedValue* dict) const override {
+  void AsValueInto(base::trace_event::TracedValue* dict) override {
     dict->SetString("type", "LoopingBeginFrameObserver");
     dict->BeginDictionary("source");
     source_->AsValueInto(dict);