cc: Compute the inflated rect to cover a fixed number of tiles.

cc/tile_priority.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_TILE_PRIORITY_H_
 #define CC_TILE_PRIORITY_H_
 
 #include <limits>
 
 #include "base/memory/ref_counted.h"
@@ skipping 78 matching lines @@
                pending.time_to_visible_in_seconds);
     distance_to_visible_in_pixels =
       std::min(active.distance_to_visible_in_pixels,
                pending.distance_to_visible_in_pixels);
   }
   void set_current_screen_quad(const gfx::QuadF& q) { current_screen_quad = q; }
 
   scoped_ptr<base::Value> AsValue() const;
 
   static const float kMaxDistanceInContentSpace;
+  static const int64 kNumTilesToCoverWithInflatedViewportRectForPrioritization;
 
   static inline float manhattanDistance(const gfx::RectF& a, const gfx::RectF& b) {
     // Compute the union explicitly.
     gfx::RectF c = gfx::RectF(
         std::min(a.x(), b.x()),
         std::min(a.y(), b.y()),
         std::max(a.right(), b.right()) - std::min(a.x(), b.x()),
         std::max(a.bottom(), b.bottom()) - std::min(a.y(), b.y()));
 
     // Rects touching the edge of the screen should not be considered visible.
@@ skipping 61 matching lines @@
   size_t memory_limit_in_bytes;
 
   TreePriority tree_priority;
 
   scoped_ptr<base::Value> AsValue() const;
 };
 
 }  // namespace cc
 
 #endif  // CC_TILE_PRIORITY_H_