Remove static thread pointers from CC

cc/video_layer_impl.cc

Index: cc/video_layer_impl.cc
diff --git a/cc/video_layer_impl.cc b/cc/video_layer_impl.cc
index 86cf037eb8baa87676451710629a73fdde0bc619..493fc07371fd28d5cacc6f0726cd59b46bd90ad5 100644
--- a/cc/video_layer_impl.cc
+++ b/cc/video_layer_impl.cc
@@ -9,7 +9,6 @@
 #include "NotImplemented.h"
 #include "cc/io_surface_draw_quad.h"
 #include "cc/layer_tree_host_impl.h"
-#include "cc/proxy.h"
 #include "cc/quad_sink.h"
 #include "cc/resource_provider.h"
 #include "cc/stream_video_draw_quad.h"
@@ -38,14 +37,12 @@ VideoLayerImpl::VideoLayerImpl(int id, WebKit::WebVideoFrameProvider* provider)
     // 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
     // the call in the destructor.
-    DCHECK(Proxy::isMainThreadBlocked());
     m_provider->setVideoFrameProviderClient(this);
 }
 
 VideoLayerImpl::~VideoLayerImpl()
 {
     // See comment in constructor for why this doesn't need a lock.
-    DCHECK(Proxy::isMainThreadBlocked());
     if (m_provider) {
         m_provider->setVideoFrameProviderClient(0);
         m_provider = 0;
@@ -88,7 +85,6 @@ static GLenum convertVFCFormatToGC3DFormat(const WebKit::WebVideoFrame& frame)
 
 void VideoLayerImpl::willDraw(ResourceProvider* resourceProvider)
 {
-    DCHECK(Proxy::isImplThread());
     LayerImpl::willDraw(resourceProvider);
 
     // Explicitly acquire and release the provider mutex so it can be held from
@@ -109,7 +105,6 @@ void VideoLayerImpl::willDraw(ResourceProvider* resourceProvider)
 
 void VideoLayerImpl::willDrawInternal(ResourceProvider* resourceProvider)
 {
-    DCHECK(Proxy::isImplThread());
     DCHECK(!m_externalTextureResource);
 
     if (!m_provider) {
@@ -154,8 +149,6 @@ void VideoLayerImpl::willDrawInternal(ResourceProvider* resourceProvider)
 
 void VideoLayerImpl::appendQuads(QuadSink& quadSink, AppendQuadsData& appendQuadsData)
 {
-    DCHECK(Proxy::isImplThread());
-
     if (!m_frame)
         return;
 
@@ -217,7 +210,6 @@ void VideoLayerImpl::appendQuads(QuadSink& quadSink, AppendQuadsData& appendQuad
 
 void VideoLayerImpl::didDraw(ResourceProvider* resourceProvider)
 {
-    DCHECK(Proxy::isImplThread());
     LayerImpl::didDraw(resourceProvider);
 
     if (!m_frame)