cc: Consider visible rect for update tile priority early out.

cc/layers/picture_layer_impl.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/layers/picture_layer_impl.h"
 
 #include <algorithm>
 #include <limits>
 #include <set>
 
@@ skipping 480 matching lines @@
 void PictureLayerImpl::UpdateTilePriorities(
     const Occlusion& occlusion_in_content_space) {
   DCHECK(!pile_->is_solid_color() || !tilings_->num_tilings());
 
   TRACE_EVENT0("cc", "PictureLayerImpl::UpdateTilePriorities");
 
   double current_frame_time_in_seconds =
       (layer_tree_impl()->CurrentBeginFrameArgs().frame_time -
        base::TimeTicks()).InSecondsF();
 
+  gfx::Rect viewport_rect_in_layer_space =
+      GetViewportForTilePriorityInContentSpace();
   bool tiling_needs_update = false;
   for (size_t i = 0; i < tilings_->num_tilings(); ++i) {
-    if (tilings_->tiling_at(i)->NeedsUpdateForFrameAtTime(
-            current_frame_time_in_seconds)) {
+    if (tilings_->tiling_at(i)->NeedsUpdateForFrameAtTimeAndViewport(
+            current_frame_time_in_seconds, viewport_rect_in_layer_space)) {
       tiling_needs_update = true;
       break;
     }
   }
   if (!tiling_needs_update)
     return;
 
-  gfx::Rect viewport_rect_in_layer_space =
-      GetViewportForTilePriorityInContentSpace();
   WhichTree tree =
       layer_tree_impl()->IsActiveTree() ? ACTIVE_TREE : PENDING_TREE;
   bool can_require_tiles_for_activation =
       !only_used_low_res_last_append_quads_ || RequiresHighResToDraw() ||
       !layer_tree_impl()->SmoothnessTakesPriority();
   for (size_t i = 0; i < tilings_->num_tilings(); ++i) {
     PictureLayerTiling* tiling = tilings_->tiling_at(i);
 
     tiling->set_can_require_tiles_for_activation(
         can_require_tiles_for_activation);
@@ skipping 1161 matching lines @@
       PictureLayerTilingSet::TilingRange tiling_range = CurrentTilingRange();
       size_t current_tiling_range_offset = current_tiling_ - tiling_range.start;
       return tiling_range.end - 1 - current_tiling_range_offset;
     }
   }
   NOTREACHED();
   return 0;
 }
 
 }  // namespace cc