cc: Start using raster/eviction iterators.

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 3b07c5dfd367897ce1e7b7524846c66c1908072a..9b37343d5338d2006b1940add6d3b8f6bb142c17 100644
--- a/cc/layers/picture_layer_impl.h
+++ b/cc/layers/picture_layer_impl.h
@@ -23,6 +23,15 @@ struct AppendQuadsData;
 class MicroBenchmarkImpl;
 class Tile;
 
+class PictureLayerImpl;
+struct CC_EXPORT PairedPictureLayer {
+  PairedPictureLayer();
+  ~PairedPictureLayer();
+
+  PictureLayerImpl* active_layer;
+  PictureLayerImpl* pending_layer;
+};
+
 class CC_EXPORT PictureLayerImpl
     : public LayerImpl,
       NON_EXPORTED_BASE(public PictureLayerTilingClient) {
@@ -112,6 +121,8 @@ class CC_EXPORT PictureLayerImpl
   virtual size_t GetMaxTilesForInterestArea() const OVERRIDE;
   virtual float GetSkewportTargetTimeInSeconds() const OVERRIDE;
   virtual int GetSkewportExtrapolationLimitInContentPixels() const OVERRIDE;
+  virtual WhichTree GetTree() const OVERRIDE;
+  virtual bool RequiresHighResToDraw() const OVERRIDE;
 
   // PushPropertiesTo active tree => pending tree.
   void SyncTiling(const PictureLayerTiling* tiling);
@@ -126,7 +137,6 @@ class CC_EXPORT PictureLayerImpl
 
   // Functions used by tile manager.
   PictureLayerImpl* GetTwinLayer() { return twin_layer_; }
-  WhichTree GetTree() const;
   bool IsOnActiveOrPendingTree() const;
   bool HasValidTilePriorities() const;
   bool AllTilesRequiredForActivationAreReadyToDraw() const;
@@ -149,13 +159,6 @@ class CC_EXPORT PictureLayerImpl
   float MinimumContentsScale() const;
   float SnappedContentsScale(float new_contents_scale);
   void ResetRasterScale();
-  void MarkVisibleResourcesAsRequired() const;
-  bool MarkVisibleTilesAsRequired(
-      PictureLayerTiling* tiling,
-      const PictureLayerTiling* optional_twin_tiling,
-      float contents_scale,
-      const gfx::Rect& rect,
-      const Region& missing_region) const;
 
   void DoPostCommitInitializationIfNeeded() {
     if (needs_post_commit_initialization_)