Remove static thread pointers from CC

cc/resource_provider.h

Index: cc/resource_provider.h
diff --git a/cc/resource_provider.h b/cc/resource_provider.h
index b20097e83edcc6baf09a6dcb45a3408ca5b540c6..308a2cfc78cbb07a7348f5d874b7d414c2653354 100644
--- a/cc/resource_provider.h
+++ b/cc/resource_provider.h
@@ -5,10 +5,12 @@
 #ifndef CCResourceProvider_h
 #define CCResourceProvider_h
 
+#include "IntRect.h"
 #include "IntSize.h"
 #include "base/basictypes.h"
 #include "base/hash_tables.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/threading/thread_checker.h"
 #include "cc/graphics_context.h"
 #include "cc/texture_copier.h"
 #include "third_party/khronos/GLES2/gl2.h"
@@ -23,13 +25,12 @@ class WebGraphicsContext3D;
 
 namespace cc {
 
-class IntRect;
 class LayerTextureSubImage;
 class TextureCopier;
 class TextureUploader;
 
-// Thread-safety notes: this class is not thread-safe and can only be called
-// from the thread it was created on (in practice, the compositor thread).
+// This class is not thread-safe and can only be called from the thread it was
+// created on (in practice, the impl thread).
 class ResourceProvider {
 public:
     typedef unsigned ResourceId;
@@ -240,7 +241,7 @@ private:
     };
     typedef base::hash_map<int, Child> ChildMap;
 
-    explicit ResourceProvider(GraphicsContext*);
+    ResourceProvider(GraphicsContext*);
     bool initialize();
 
     const Resource* lockForRead(ResourceId);
@@ -269,6 +270,8 @@ private:
     scoped_ptr<AcceleratedTextureCopier> m_textureCopier;
     int m_maxTextureSize;
 
+    base::ThreadChecker m_threadChecker;
+
     DISALLOW_COPY_AND_ASSIGN(ResourceProvider);
 };