Reland: cc: Fix size_t to int truncations in layers/ output/ playback/ quads/

cc/layers/layer_iterator.h

 // Copyright 2012 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_ITERATOR_H_
 #define CC_LAYERS_LAYER_ITERATOR_H_
 
 #include "cc/base/cc_export.h"
 #include "cc/trees/layer_tree_host_common.h"
 
@@ skipping 64 matching lines @@
 // by incrementing the stepping iterator while it is != to
 // the end iterator. At each step the iterator knows what the layer
 // is representing, and you can query the iterator to decide
 // what actions to perform with the layer given what it represents.
 
 ////////////////////////////////////////////////////////////////////////////////
 
 // Non-templated constants
 struct LayerIteratorValue {
   static const int kInvalidTargetRenderSurfaceLayerIndex = -1;
-  // This must be -1 since the iterator action code assumes that this value can
-  // be reached by subtracting one from the position of the first layer in the
-  // current target surface's child layer list, which is 0.
-  static const int kLayerIndexRepresentingTargetRenderSurface = -1;
+  // This must be (size_t)-1 since the iterator action code assumes that this
+  // value can be reached by subtracting one from the position of the first
+  // layer in the current target surface's child layer list, which is 0.
+  static const size_t kLayerIndexRepresentingTargetRenderSurface =
+      static_cast<size_t>(-1);
 };
 
 // The position of a layer iterator that is independent
 // of its many template types.
 template <typename LayerType> struct LayerIteratorPosition {
   bool represents_target_render_surface;
   bool represents_contributing_render_surface;
   bool represents_itself;
   LayerType* target_render_surface_layer;
   LayerType* current_layer;
@@ skipping 180 matching lines @@
   // owns the current target surface. This is a value from 0 to n-1
   // (n = size of render_surface_layer_list = number of surfaces).
   // A value outside of this range
   // (for example, LayerIteratorValue::kInvalidTargetRenderSurfaceLayerIndex)
   // is used to indicate a position outside the bounds of the tree.
   int target_render_surface_layer_index_;
   // A position in the list of layers that are children of the
   // current target surface. When pointing to one of these layers,
   // this is a value from 0 to n-1 (n = number of children).
   // Since the iterator must also stop at the layers representing
-  // the target surface, this is done by setting the current_layerIndex
-  // to a value of LayerIteratorValue::LayerRepresentingTargetRenderSurface.
-  int current_layer_index_;
+  // the target surface, this is done by setting the current_layer_index
+  // to a value of
+  // LayerIteratorValue::kLayerIndexRepresentingTargetRenderSurface.
+  size_t current_layer_index_;
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_LAYER_ITERATOR_H_