cc: Make tiling interest rect calc based on viewport.

cc/resources/picture_layer_tiling.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/picture_layer_tiling.h"
 
 #include <algorithm>
 #include <cmath>
 #include <limits>
 #include <set>
@@ skipping 15 matching lines @@
 const float kSoonBorderDistanceViewportPercentage = 0.15f;
 const float kMaxSoonBorderDistanceInScreenPixels = 312.f;
 
 }  // namespace
 
 scoped_ptr<PictureLayerTiling> PictureLayerTiling::Create(
     WhichTree tree,
     float contents_scale,
     scoped_refptr<RasterSource> raster_source,
     PictureLayerTilingClient* client,
-    size_t max_tiles_for_interest_area,
+    float tiling_interest_area_viewport_multiplier,
     float skewport_target_time_in_seconds,
     int skewport_extrapolation_limit_in_content_pixels) {
   return make_scoped_ptr(new PictureLayerTiling(
-      tree, contents_scale, raster_source, client, max_tiles_for_interest_area,
-      skewport_target_time_in_seconds,
+      tree, contents_scale, raster_source, client,
+      tiling_interest_area_viewport_multiplier, skewport_target_time_in_seconds,
       skewport_extrapolation_limit_in_content_pixels));
 }
 
 PictureLayerTiling::PictureLayerTiling(
     WhichTree tree,
     float contents_scale,
     scoped_refptr<RasterSource> raster_source,
     PictureLayerTilingClient* client,
-    size_t max_tiles_for_interest_area,
+    float tiling_interest_area_viewport_multiplier,
     float skewport_target_time_in_seconds,
     int skewport_extrapolation_limit_in_content_pixels)
-    : max_tiles_for_interest_area_(max_tiles_for_interest_area),
+    : tiling_interest_area_viewport_multiplier_(
+          tiling_interest_area_viewport_multiplier),
       skewport_target_time_in_seconds_(skewport_target_time_in_seconds),
       skewport_extrapolation_limit_in_content_pixels_(
           skewport_extrapolation_limit_in_content_pixels),
       contents_scale_(contents_scale),
       client_(client),
       tree_(tree),
       raster_source_(raster_source),
       resolution_(NON_IDEAL_RESOLUTION),
       tiling_data_(gfx::Size(), gfx::Size(), kBorderTexels),
       can_require_tiles_for_activation_(false),
@@ skipping 504 matching lines @@
     const gfx::Rect& viewport_in_layer_space,
     float ideal_contents_scale,
     double current_frame_time_in_seconds,
     const Occlusion& occlusion_in_layer_space) {
   if (!NeedsUpdateForFrameAtTimeAndViewport(current_frame_time_in_seconds,
                                             viewport_in_layer_space)) {
     // This should never be zero for the purposes of has_ever_been_updated().
     DCHECK_NE(current_frame_time_in_seconds, 0.0);
     return false;
   }
-
   gfx::Rect visible_rect_in_content_space =
       gfx::ScaleToEnclosingRect(viewport_in_layer_space, contents_scale_);
 
   if (tiling_size().IsEmpty()) {
     UpdateVisibleRectHistory(current_frame_time_in_seconds,
                              visible_rect_in_content_space);
     last_viewport_in_layer_space_ = viewport_in_layer_space;
     return false;
   }
 
   // Calculate the skewport.
   gfx::Rect skewport = ComputeSkewport(current_frame_time_in_seconds,
                                        visible_rect_in_content_space);
   DCHECK(skewport.Contains(visible_rect_in_content_space));
 
   // Calculate the eventually/live tiles rect.
-  gfx::Size tile_size = tiling_data_.max_texture_size();
-  int64 eventually_rect_area =
-      max_tiles_for_interest_area_ * tile_size.width() * tile_size.height();
+  int64 eventually_rect_area = tiling_interest_area_viewport_multiplier_ *
+                               visible_rect_in_content_space.width() *
+                               visible_rect_in_content_space.height();
 
   gfx::Rect eventually_rect =
       ExpandRectEquallyToAreaBoundedBy(visible_rect_in_content_space,
                                        eventually_rect_area,
                                        gfx::Rect(tiling_size()),
                                        &expansion_cache_);
 
   DCHECK(eventually_rect.IsEmpty() ||
          gfx::Rect(tiling_size()).Contains(eventually_rect))
       << "tiling_size: " << tiling_size().ToString()
@@ skipping 427 matching lines @@
       break;
   }
 
   gfx::Rect result(origin_x, origin_y, width, height);
   if (cache)
     cache->previous_result = result;
   return result;
 }
 
 }  // namespace cc