[cast] Handle frame size changes directly in the VideoToolbox encoder (v2).

media/cast/sender/h264_vt_encoder_unittest.cc

Index: media/cast/sender/h264_vt_encoder_unittest.cc
diff --git a/media/cast/sender/h264_vt_encoder_unittest.cc b/media/cast/sender/h264_vt_encoder_unittest.cc
index 04f3d629da95b23a9d9f8786347b5eb691ddacfd..4be1b93c7606b9d309b22957c961c6a484e0404b 100644
--- a/media/cast/sender/h264_vt_encoder_unittest.cc
+++ b/media/cast/sender/h264_vt_encoder_unittest.cc
@@ -208,8 +208,6 @@ class H264VideoToolboxEncoderTest : public ::testing::Test {
     encoder_.reset(new H264VideoToolboxEncoder(
         cast_environment_,
         video_sender_config_,
-        gfx::Size(kVideoWidth, kVideoHeight),
-        0u,
         base::Bind(&SaveOperationalStatus, &operational_status_)));
     message_loop_.RunUntilIdle();
     EXPECT_EQ(STATUS_INITIALIZED, operational_status_);
@@ -306,10 +304,12 @@ TEST_F(H264VideoToolboxEncoderTest, CheckFramesAreDecodable) {
 TEST_F(H264VideoToolboxEncoderTest, CheckVideoFrameFactory) {
   auto video_frame_factory = encoder_->CreateVideoFrameFactory();
   ASSERT_TRUE(video_frame_factory.get());
-  CreateFrameAndMemsetPlane(video_frame_factory.get());
-  // TODO(jfroy): Need to test that the encoder can encode VideoFrames provided
-  // by the VideoFrameFactory.
-  encoder_.reset();
+  // The first call to |MaybeCreateFrame| will return null but post a task to
+  // the encoder to initialize for the specified frame size. We then drain the
+  // message loop. After that, the encoder should have initialized and we
+  // request a frame again.
+  ASSERT_FALSE(video_frame_factory->MaybeCreateFrame(
+      gfx::Size(kVideoWidth, kVideoHeight), base::TimeDelta()));
   message_loop_.RunUntilIdle();
   CreateFrameAndMemsetPlane(video_frame_factory.get());
 }