cc: Remove vectors from tiling eviction tile iterator.

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 d49205137510bd9d5f3bc57e89a785d42de65616..2d0bccb92f31c3ee0425976183ee1ecd031c1ea2 100644
--- a/cc/layers/picture_layer_impl.h
+++ b/cc/layers/picture_layer_impl.h
@@ -77,15 +77,40 @@ class CC_EXPORT PictureLayerImpl
     operator bool() const;
 
    private:
+    enum RangeType {
+      HIGHER_THAN_HIGH_RES,
+      LOWER_THAN_LOW_RES,
+      BETWEEN_HIGH_AND_LOW_RES,
+      LOW_RES,
+      HIGH_RES,
+      NUM_RANGE_TYPES
+    };
+    struct TilingIterationRange {
+      int start_index;
+      int one_past_end_index;
+    };
+    struct IterationStage {
+      IterationStage(TilePriority::PriorityBin type, bool is_required)
+          : tile_type(type), required_for_activation(is_required) {}
+
+      TilePriority::PriorityBin tile_type;
+      bool required_for_activation;
+    };
+
+    void ConstructRanges();
+    bool CurrentTilingIndexInRange();
     void AdvanceToNextIterator();
-    bool IsCorrectType(
-        PictureLayerTiling::TilingEvictionTileIterator* it) const;
+    bool AdvanceTiling();
+    bool AdvanceRange();
+    bool AdvanceStage();
 
-    std::vector<PictureLayerTiling::TilingEvictionTileIterator> iterators_;
-    size_t iterator_index_;
-    TilePriority::PriorityBin iteration_stage_;
-    bool required_for_activation_;
+    PictureLayerTiling::TilingEvictionTileIterator iterator_;
+    int current_tiling_index_;
+    RangeType current_range_type_;
+    IterationStage current_stage_;
 
+    TilingIterationRange ranges_[NUM_RANGE_TYPES];
+    TreePriority tree_priority_;
     PictureLayerImpl* layer_;
   };