Preliminary compositor disabling patch.

cc/quads/render_pass.h

Index: cc/quads/render_pass.h
diff --git a/cc/quads/render_pass.h b/cc/quads/render_pass.h
index 46a8084b387da41a0be55d0974a4bd3c38372a20..9898da3e2991472b9030186edfccc39b6dddc550 100644
--- a/cc/quads/render_pass.h
+++ b/cc/quads/render_pass.h
@@ -74,6 +74,7 @@ class CC_EXPORT RenderPass {
   void SetAll(RenderPassId id,
               const gfx::Rect& output_rect,
               const gfx::Rect& damage_rect,
+              const gfx::Rect& overlay_rect,
               const gfx::Transform& transform_to_root_target,
               bool has_transparent_background);
 
@@ -93,12 +94,22 @@ class CC_EXPORT RenderPass {
   DrawQuad* CopyFromAndAppendDrawQuad(const DrawQuad* quad,
                                       const SharedQuadState* shared_quad_state);
 
+  // Recalculates |overlay_damage|, call this when overlay quads are removed
+  // from the list.
+  void RecalculateOverlayDamage();
+
+  // Unions |overlay_rect| into |damage_rect|.
+  void UnionOverlayDamage();
+
+  gfx::Rect GetFullDamageRect();
+
   // Uniquely identifies the render pass in the compositor's current frame.
   RenderPassId id;
 
   // These are in the space of the render pass' physical pixels.
   gfx::Rect output_rect;
   gfx::Rect damage_rect;
+  gfx::Rect overlay_rect;
 
   // Transforms from the origin of the |output_rect| to the origin of the root
   // render pass' |output_rect|.