Add logic to GLRenderer to support RenderPassDrawQuad copying.

cc/output/direct_renderer.h

Index: cc/output/direct_renderer.h
diff --git a/cc/output/direct_renderer.h b/cc/output/direct_renderer.h
index d0687cd19902a85415fce60240c9310787639724..e2bc3a43318f4cb23eea00f088f66ee370d00d22 100644
--- a/cc/output/direct_renderer.h
+++ b/cc/output/direct_renderer.h
@@ -27,7 +27,8 @@ class ResourceProvider;
 // This is the base class for code shared between the GL and software
 // renderer implementations.  "Direct" refers to the fact that it does not
 // delegate rendering to another compositor.
-class CC_EXPORT DirectRenderer : public Renderer {
+class CC_EXPORT DirectRenderer : public Renderer,
+                                 public RenderPassDrawQuadCopier {
  public:
   ~DirectRenderer() override;