Initialize cc::VideoFrameProviderClientImpl::active_video_layer_.

As of r259048, WebMediaPlayerImpl now notifies the compositor of new
frames directly on the compositing thread. If
VideoFrameProviderClientImpl::DidRecieveFrame() is called before
VideoLayerImpl::DidBecomeActive() is called,
VideoFrameProviderClientImpl may attempt to call
VideoLayerImpl::SetNeedsRedraw() using an uninitialized pointer.

BUG=357145
R=enne@chromium.org

Review URL: https://codereview.chromium.org/214543011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@260360 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 22 insertions, 1 deletions

diff --git a/cc/layers/video_frame_provider_client_impl.cc b/cc/layers/video_frame_provider_client_impl.cc
index 732bbbb..9071fdc 100644
--- a/cc/layers/video_frame_provider_client_impl.cc
+++ b/cc/layers/video_frame_provider_client_impl.cc
@@ -22,7 +22,7 @@ VideoFrameProviderClientImpl::~VideoFrameProviderClientImpl() {}
 
 VideoFrameProviderClientImpl::VideoFrameProviderClientImpl(
     VideoFrameProvider* provider)
-    : provider_(provider) {
+    : active_video_layer_(NULL), provider_(provider) {
   // This only happens during a commit on the compositor thread while the main
   // thread is blocked. That makes this a thread-safe call to set the video
   // frame provider client that does not require a lock. The same is true of
diff --git a/cc/layers/video_frame_provider_client_impl.h b/cc/layers/video_frame_provider_client_impl.h
index 2bcb446..e676d0b 100644
--- a/cc/layers/video_frame_provider_client_impl.h
+++ b/cc/layers/video_frame_provider_client_impl.h
@@ -22,6 +22,7 @@ class VideoFrameProviderClientImpl
   static scoped_refptr<VideoFrameProviderClientImpl> Create(
       VideoFrameProvider* provider);
 
+  VideoLayerImpl* active_video_layer() { return active_video_layer_; }
   void set_active_video_layer(VideoLayerImpl* video_layer) {
     active_video_layer_ = video_layer;
   }
diff --git a/cc/layers/video_layer_impl_unittest.cc b/cc/layers/video_layer_impl_unittest.cc
index dc9c6fb..68a2b2e 100644
--- a/cc/layers/video_layer_impl_unittest.cc
+++ b/cc/layers/video_layer_impl_unittest.cc
@@ -4,6 +4,7 @@
 
 #include "cc/layers/video_layer_impl.h"
 
+#include "cc/layers/video_frame_provider_client_impl.h"
 #include "cc/output/context_provider.h"
 #include "cc/output/output_surface.h"
 #include "cc/test/fake_video_frame_provider.h"
@@ -76,5 +77,22 @@ TEST(VideoLayerImplTest, Occlusion) {
   }
 }
 
+TEST(VideoLayerImplTest, DidBecomeActiveShouldSetActiveVideoLayer) {
+  LayerTestCommon::LayerImplTest impl;
+  DebugScopedSetImplThreadAndMainThreadBlocked thread(impl.proxy());
+
+  FakeVideoFrameProvider provider;
+  VideoLayerImpl* video_layer_impl =
+      impl.AddChildToRoot<VideoLayerImpl>(&provider);
+
+  VideoFrameProviderClientImpl* client =
+      static_cast<VideoFrameProviderClientImpl*>(provider.client());
+  ASSERT_TRUE(client);
+  EXPECT_FALSE(client->active_video_layer());
+
+  video_layer_impl->DidBecomeActive();
+  EXPECT_EQ(video_layer_impl, client->active_video_layer());
+}
+
 }  // namespace
 }  // namespace cc
diff --git a/cc/test/fake_video_frame_provider.h b/cc/test/fake_video_frame_provider.h
index 972d8f8..fc462e4 100644
--- a/cc/test/fake_video_frame_provider.h
+++ b/cc/test/fake_video_frame_provider.h
@@ -21,6 +21,8 @@ class FakeVideoFrameProvider : public VideoFrameProvider {
   virtual void PutCurrentFrame(const scoped_refptr<media::VideoFrame>&)
       OVERRIDE {}
 
+  Client* client() { return client_; }
+
   void set_frame(const scoped_refptr<media::VideoFrame>& frame) {
     frame_ = frame;
   }