Makes copying layers clone external textures.

content/common/gpu/client/gl_helper.h

Index: content/common/gpu/client/gl_helper.h
diff --git a/content/common/gpu/client/gl_helper.h b/content/common/gpu/client/gl_helper.h
index c204477124cce3ef4f9d8082d7d930371a784022..8157c9a96bed913ece6b6a2ceaa4ff35fc6c3f66 100644
--- a/content/common/gpu/client/gl_helper.h
+++ b/content/common/gpu/client/gl_helper.h
@@ -39,6 +39,10 @@ class GLHelper {
                      unsigned char* out,
                      const base::Callback<void(bool)>& callback);
 
+  // Creates a copy of the specified texture. |size| is the size of the texture.
+  WebKit::WebGLId CopyTexture(WebKit::WebGLId texture,
+                              const gfx::Size& size);
+
   // Returns the shader compiled from the source.
   WebKit::WebGLId CompileShaderFromSource(const WebKit::WGC3Dchar* source,
                                           WebKit::WGC3Denum type);
@@ -46,6 +50,9 @@ class GLHelper {
  private:
   class CopyTextureToImpl;
 
+  // Creates |copy_texture_to_impl_| if NULL.
+  void InitCopyTextToImpl();
+
   WebKit::WebGraphicsContext3D* context_;
   WebKit::WebGraphicsContext3D* context_for_thread_;
   scoped_ptr<CopyTextureToImpl> copy_texture_to_impl_;