WIP - compositor worker mega patch.

content/renderer/gpu/render_widget_compositor.h

Index: content/renderer/gpu/render_widget_compositor.h
diff --git a/content/renderer/gpu/render_widget_compositor.h b/content/renderer/gpu/render_widget_compositor.h
index 0eac7cd9739241ff7fd56d0fc482ab1c59a8ad0b..3f35254033234678646ca0098340ae7b8e210946 100644
--- a/content/renderer/gpu/render_widget_compositor.h
+++ b/content/renderer/gpu/render_widget_compositor.h
@@ -139,6 +139,8 @@ class CONTENT_EXPORT RenderWidgetCompositor
   void setShowDebugBorders(bool show) override;
   void setShowScrollBottleneckRects(bool show) override;
 
+  void setMutatorClient(blink::WebCompositorMutatorClient*) override;
+
   void updateTopControlsState(blink::WebTopControlsState constraints,
                               blink::WebTopControlsState current,
                               bool animate) override;
@@ -156,6 +158,8 @@ class CONTENT_EXPORT RenderWidgetCompositor
                            const gfx::Vector2dF& elastic_overscroll_delta,
                            float page_scale,
                            float top_controls_delta) override;
+  void ApplyMutations(
+      const cc::LayerTreeMutations& mutations) override;
   void RequestNewOutputSurface() override;
   void DidInitializeOutputSurface() override;
   void DidFailToInitializeOutputSurface() override;