Add BeginFrameObserverProxy

ui/compositor/compositor_unittest.cc

Index: ui/compositor/compositor_unittest.cc
diff --git a/ui/compositor/compositor_unittest.cc b/ui/compositor/compositor_unittest.cc
index 810f1c96d0875938de0b2460aaddcb4eaf4568f4..35f6c5a3718073587ad8fad0dc88de469e52326d 100644
--- a/ui/compositor/compositor_unittest.cc
+++ b/ui/compositor/compositor_unittest.cc
@@ -3,13 +3,24 @@
 // found in the LICENSE file.
 
 #include "base/test/test_simple_task_runner.h"
+#include "cc/output/begin_frame_args.h"
+#include "cc/test/begin_frame_args_test.h"
+#include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/compositor/compositor.h"
 #include "ui/compositor/test/context_factories_for_test.h"
 
+using testing::Mock;
+using testing::_;
+
 namespace ui {
 namespace {
 
+class MockCompositorBeginFrameObserver : public CompositorBeginFrameObserver {
+ public:
+  MOCK_METHOD1(OnSendBeginFrame, void(const cc::BeginFrameArgs&));
+};
+
 // Test fixture for tests that require a ui::Compositor with a real task
 // runner.
 class CompositorTest : public testing::Test {
@@ -61,4 +72,41 @@ TEST_F(CompositorTest, LocksTimeOut) {
   EXPECT_TRUE(compositor()->IsLocked());
 }
 
+// Tests whether |missed_begin_frame_args_| is used immediately or not when new
+// observer is added.
+TEST_F(CompositorTest, AddBeginFrameObserver) {
+  cc::BeginFrameArgs last_args =
+    cc::CreateBeginFrameArgsForTesting(BEGINFRAME_FROM_HERE,
+                                       base::TimeTicks::FromInternalValue(33));
+  cc::BeginFrameArgs new_args =
+    cc::CreateBeginFrameArgsForTesting(BEGINFRAME_FROM_HERE,
+                                       base::TimeTicks::FromInternalValue(55));
+
+  // Simulate to trigger new BeginFrame by using |new_args|.
+  compositor()->SendBeginFramesToChildren(new_args);
+  // |new_args| is stored in |missed_begin_frame_args_| in Compositor for using
+  // later added observers.
+  EXPECT_EQ(new_args.frame_time,
+            compositor()->MissedBeginFrameArgsForTesting().frame_time);

[danakj, 2015/03/17 18:56:45]

I don't think you need this check (or the ForTesting method). You care that
Compositor sends the args, not how it stores it.

[simonhong, 2015/03/19 15:48:46]

Removed.

+
+  // When |missed_begin_frame_args_| is sent, its type is set to MISSED.
+  cc::BeginFrameArgs expected_args(new_args);
+  expected_args.type = cc::BeginFrameArgs::MISSED;
+
+  MockCompositorBeginFrameObserver test_observer;
+  EXPECT_CALL(test_observer, OnSendBeginFrame(expected_args));

[danakj, 2015/03/17 18:56:45]

This is the right level of testing here.

+  // When new observer is added, Compositor immediately sends BeginFrame with
+  // |missed_begin_frame_args_| when new observer didn't used it.
+  compositor()->AddBeginFrameObserver(&test_observer, last_args);
+  compositor()->RemoveBeginFrameObserver(&test_observer);
+  Mock::VerifyAndClearExpectations(&test_observer);
+
+  EXPECT_CALL(test_observer, OnSendBeginFrame(_)).Times(0);
+  //test_observer.Reset();
+  // BeginFrame is not sended immediately because new observer already used
+  // |missed_begin_frame_args_|.
+  compositor()->AddBeginFrameObserver(&test_observer, new_args);
+  compositor()->RemoveBeginFrameObserver(&test_observer);
+}
+
 }  // namespace ui