cc: Use CheckedNumeric for resource size calculations.

cc/trees/layer_tree_host.cc

 // 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.
 
 #include "cc/trees/layer_tree_host.h"
 
 #include <algorithm>
 #include <stack>
 #include <string>
 
@@ skipping 915 matching lines @@
     const RenderSurfaceLayerList& update_list) {
   size_t readback_bytes = 0;
   size_t contents_texture_bytes = 0;
 
   // Start iteration at 1 to skip the root surface as it does not have a texture
   // cost.
   for (size_t i = 1; i < update_list.size(); ++i) {
     Layer* render_surface_layer = update_list.at(i);
     RenderSurface* render_surface = render_surface_layer->render_surface();
 
-    size_t bytes =
-        Resource::MemorySizeBytes(render_surface->content_rect().size(),
-                                  RGBA_8888);
+    // We can use UncheckedMemorySizeBytes, since render surface content rect is
+    // limited by max texture size.
+    size_t bytes = Resource::UncheckedMemorySizeBytes(
+        render_surface->content_rect().size(), RGBA_8888);
     contents_texture_bytes += bytes;
 
     if (render_surface_layer->background_filters().IsEmpty() &&
         render_surface_layer->uses_default_blend_mode())
       continue;
 
     if (!readback_bytes) {
-      readback_bytes = Resource::MemorySizeBytes(device_viewport_size_,
-                                                 RGBA_8888);
+      // We need to use a checked size calucation here, since we don't control
+      // the size of the device viewport.
+      readback_bytes =
+          Resource::CheckedMemorySizeBytes(device_viewport_size_, RGBA_8888);
     }
   }
   return readback_bytes + contents_texture_bytes;
 }
 
 void LayerTreeHost::PaintMasksForRenderSurface(Layer* render_surface_layer,
                                                ResourceUpdateQueue* queue,
                                                bool* did_paint_content,
                                                bool* need_more_updates) {
   // Note: Masks and replicas only exist for layers that own render surfaces. If
@@ skipping 338 matching lines @@
     const BeginFrameArgs& args) const {
   client_->SendBeginFramesToChildren(args);
 }
 
 void LayerTreeHost::SetAuthoritativeVSyncInterval(
     const base::TimeDelta& interval) {
   proxy_->SetAuthoritativeVSyncInterval(interval);
 }
 
 }  // namespace cc