cc: Don't swap PictureLayerTilingSet on activate.

cc/layers/picture_layer_impl.h

Index: cc/layers/picture_layer_impl.h
diff --git a/cc/layers/picture_layer_impl.h b/cc/layers/picture_layer_impl.h
index d8ab0366268fa7c0995d73c81838e92d1b6e18df..c1d80c6ecfa0d42325b67401e0bcca62413aac55 100644
--- a/cc/layers/picture_layer_impl.h
+++ b/cc/layers/picture_layer_impl.h
@@ -113,7 +113,6 @@ class CC_EXPORT PictureLayerImpl
   // Mask-related functions.
   void GetContentsResourceId(ResourceProvider::ResourceId* resource_id,
                              gfx::Size* resource_size) const override;
-  void set_is_mask(bool is_mask) { is_mask_ = is_mask; }
 
   size_t GPUMemoryUsageInBytes() const override;
 
@@ -136,7 +135,6 @@ class CC_EXPORT PictureLayerImpl
   PictureLayerImpl(LayerTreeImpl* tree_impl, int id);
   PictureLayerTiling* AddTiling(float contents_scale);
   void RemoveAllTilings();
-  void SyncFromActiveLayer(const PictureLayerImpl* other);
   void AddTilingsForRasterScale();
   void UpdateTilePriorities(const Occlusion& occlusion_in_content_space);
   virtual bool ShouldAdjustRasterScale() const;
@@ -147,7 +145,10 @@ class CC_EXPORT PictureLayerImpl
   void ResetRasterScale();
   gfx::Rect GetViewportForTilePriorityInContentSpace() const;
   PictureLayerImpl* GetRecycledTwinLayer() const;
-  void UpdateRasterSource(scoped_refptr<RasterSource> raster_source);
+  void UpdateRasterSource(scoped_refptr<RasterSource> raster_source,
+                          Region* new_invalidation,
+                          bool is_mask,

[enne (OOO), 2014/12/01 22:08:17]

I'm a little not sure about this mask parameter in UpdateRasterSource, because
it makes it appear like being a mask can change.  (The previous API wasn't much
better.)  Layers don't change from being masks to not masks.  PictureLayerImpl
at least should never change.  PictureLayer just gets SetIsMask(true) via
SetMaskLayer and then can't ever change back.  Should is_mask be a constructor
parameter to PictureLayerImpl?

[danakj, 2014/12/05 22:30:44]

Yes, that would be ideal if blink can actually do that. I will add a TODO.

[enne (OOO), 2014/12/05 23:02:02]

Sorry.  It'd be ideal if Blink could do that for PictureLayer.  However, you can
make it a constructor parameter for PictureLayerImpl now?

[danakj, 2014/12/06 17:14:08]

Yah I guess so. I'll just dcheck in picture layer if it changes then

+                          const PictureLayerTilingSet* pending_set);
 
   void DoPostCommitInitializationIfNeeded() {
     if (needs_post_commit_initialization_)