cc: Replace LayerIterator with iterator that walks layer list and effect tree

cc/layers/layer_impl.h

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_LAYERS_LAYER_IMPL_H_
 #define CC_LAYERS_LAYER_IMPL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 398 matching lines @@
   // Get the correct invalidation region instead of conservative Rect
   // for layers that provide it.
   virtual Region GetInvalidationRegionForDebugging();
 
   virtual gfx::Rect GetEnclosingRectInTargetSpace() const;
 
   int num_copy_requests_in_target_subtree();
 
   void UpdatePropertyTreeForScrollingAndAnimationIfNeeded();
 
-  bool IsHidden() const;
-
   float GetIdealContentsScale() const;
 
   bool was_ever_ready_since_last_transform_animation() const {
     return was_ever_ready_since_last_transform_animation_;
   }
 
   void set_was_ever_ready_since_last_transform_animation(bool was_ready) {
     was_ever_ready_since_last_transform_animation_ = was_ready;
   }
 
@@ skipping 132 matching lines @@
   // the overlay scrollbars. It's set on the scroll layer (not the scrollbar
   // layers) and consumed by LayerTreeImpl::PushPropertiesTo during activation.
   bool needs_show_scrollbars_ : 1;
 
   DISALLOW_COPY_AND_ASSIGN(LayerImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_LAYER_IMPL_H_