Initialize cc::VideoFrameProviderClientImpl::active_video_layer_ to NULL.

cc/layers/video_frame_provider_client_impl.cc

Index: cc/layers/video_frame_provider_client_impl.cc
diff --git a/cc/layers/video_frame_provider_client_impl.cc b/cc/layers/video_frame_provider_client_impl.cc
index 732bbbb1d0a426fe2097a81bd3263f95ff3bd375..9071fdc404061a38fa12be87d2f7c39655d27281 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