[#2] Pass gfx structs by const ref (gfx::Rect, gfx::RectF)

cc/resources/priority_calculator.cc

 // 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.
 
 #include "cc/resources/priority_calculator.h"
 
 #include <algorithm>
 
 #include "ui/gfx/rect.h"
 
@@ skipping 51 matching lines @@
 
 // static
 int PriorityCalculator::LingeringPriority(int previous_priority) {
   // TODO(reveman): We should remove this once we have priorities for all
   // textures (we can't currently calculate distances for off-screen textures).
   return std::min(kLingeringLimitPriority,
                   std::max(kLingeringBasePriority, previous_priority + 1));
 }
 
 // static
-int PriorityCalculator::PriorityFromDistance(gfx::Rect visible_rect,
-                                             gfx::Rect texture_rect,
+int PriorityCalculator::PriorityFromDistance(const gfx::Rect& visible_rect,
+                                             const gfx::Rect& texture_rect,
                                              bool draws_to_root_surface) {
   int distance = visible_rect.ManhattanInternalDistance(texture_rect);
   if (!distance)
     return VisiblePriority(draws_to_root_surface);
   return std::min(kNotVisibleLimitPriority, kNotVisibleBasePriority + distance);
 }
 
 // static
 int PriorityCalculator::SmallAnimatedLayerMinPriority() {
   return kSmallAnimatedLayerPriority;
@@ skipping 23 matching lines @@
 int PriorityCalculator::AllowVisibleAndNearbyCutoff() {
   return kVisibleAndNearbyPriorityCutoff;
 }
 
 // static
 int PriorityCalculator::AllowEverythingCutoff() {
   return kEverythingPriorityCutoff;
 }
 
 }  // namespace cc