[cc] Track observer status in ExternalBeginFrameSource.

cc/test/begin_frame_source_test.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_TEST_BEGIN_FRAME_SOURCE_TEST_H_
 #define CC_TEST_BEGIN_FRAME_SOURCE_TEST_H_
 
 #include "base/trace_event/trace_event_argument.h"
 #include "cc/scheduler/begin_frame_source.h"
 #include "cc/test/begin_frame_args_test.h"
@@ skipping 19 matching lines @@
 
 #define EXPECT_BEGIN_FRAME_USED_MISSED(obs, source_id, sequence_number,        \
                                        frame_time, deadline, interval)         \
   EXPECT_CALL(                                                                 \
       (obs), OnBeginFrame(CreateBeginFrameArgsForTesting(                      \
                  BEGINFRAME_FROM_HERE, source_id, sequence_number, frame_time, \
                  deadline, interval, BeginFrameArgs::MISSED)))                 \
       .InSequence((obs).sequence)                                              \
       .WillOnce(::testing::SaveArg<0>(&((obs).last_begin_frame_args)))
 
+#define EXPECT_BEGIN_FRAME_ARGS_DROP(obs, args) \
+  EXPECT_CALL((obs), OnBeginFrame(args)).Times(1).InSequence((obs).sequence)
+
+#define EXPECT_BEGIN_FRAME_ARGS_USED(obs, args) \
+  EXPECT_CALL((obs), OnBeginFrame(args))        \
+      .InSequence((obs).sequence)               \
+      .WillOnce(::testing::SaveArg<0>(&((obs).last_begin_frame_args)))
+
 #define EXPECT_BEGIN_FRAME_SOURCE_PAUSED(obs, paused)         \
   EXPECT_CALL((obs), OnBeginFrameSourcePausedChanged(paused)) \
       .Times(1)                                               \
       .InSequence((obs).sequence)
 
 // Macros to send BeginFrameArgs on a FakeBeginFrameSink (and verify resulting
 // observer behaviour).
 #define SEND_BEGIN_FRAME(args_equal_to, source, sequence_number, frame_time, \
                          deadline, interval)                                 \
   {                                                                          \
@@ skipping 35 matching lines @@
   MockBeginFrameObserver();
   virtual ~MockBeginFrameObserver();
 
   BeginFrameArgs last_begin_frame_args;
   ::testing::Sequence sequence;
 };
 
 }  // namespace cc
 
 #endif  // CC_TEST_BEGIN_FRAME_SOURCE_TEST_H_