cc: Make GetViewportForTilePriorityInContentSpace() not need intersect.

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 468 matching lines @@
             current_frame_time_in_seconds)) {
       tiling_needs_update = true;
       break;
     }
   }
   if (!tiling_needs_update)
     return;
 
   gfx::Rect visible_rect_in_content_space(
       GetViewportForTilePriorityInContentSpace());
-  visible_rect_in_content_space.Intersect(visible_content_rect());
   gfx::Rect visible_layer_rect = gfx::ScaleToEnclosingRect(
       visible_rect_in_content_space, 1.f / contents_scale_x());
   WhichTree tree =
       layer_tree_impl()->IsActiveTree() ? ACTIVE_TREE : PENDING_TREE;
   for (size_t i = 0; i < tilings_->num_tilings(); ++i) {
     tilings_->tiling_at(i)->UpdateTilePriorities(tree,
                                                  visible_layer_rect,
                                                  ideal_contents_scale_,
                                                  current_frame_time_in_seconds,
                                                  occlusion_in_content_space);
@@ skipping 17 matching lines @@
     if (screen_space_transform_for_tile_priority_.GetInverse(&view_to_layer)) {
       // Transform from view space to content space.
       visible_rect_in_content_space =
           gfx::ToEnclosingRect(MathUtil::ProjectClippedRect(
               view_to_layer, viewport_rect_for_tile_priority_));
 
       visible_rect_in_content_space.Intersect(gfx::Rect(content_bounds()));
     }
   }
 
+  visible_rect_in_content_space.Intersect(visible_content_rect());
   return visible_rect_in_content_space;
 }
 
 PictureLayerImpl* PictureLayerImpl::GetRecycledTwinLayer() {
   // TODO(vmpstr): Maintain recycled twin as a member. crbug.com/407418
   return static_cast<PictureLayerImpl*>(
       layer_tree_impl()->FindRecycleTreeLayerById(id()));
 }
 
 void PictureLayerImpl::NotifyTileStateChanged(const Tile* tile) {
@@ skipping 245 matching lines @@
   DCHECK_GT(tilings_->num_tilings(), 0u);
 
   // The goal of this function is to find the minimum set of tiles that need to
   // be ready to draw in order to activate without flashing content from a
   // higher res on the active tree to a lower res on the pending tree.
 
   // First, early out for layers with no visible content.
   if (visible_content_rect().IsEmpty())
     return;
 
-  gfx::Rect rect(visible_content_rect());
-
   // Only mark tiles inside the viewport for tile priority as required for
   // activation. This viewport is normally the same as the draw viewport but
   // can be independently overridden by embedders like Android WebView with
   // SetExternalDrawConstraints.
-  rect.Intersect(GetViewportForTilePriorityInContentSpace());
+  gfx::Rect rect = GetViewportForTilePriorityInContentSpace();
 
   float min_acceptable_scale =
       std::min(raster_contents_scale_, ideal_contents_scale_);
 
   if (PictureLayerImpl* twin = twin_layer_) {
     float twin_min_acceptable_scale =
         std::min(twin->ideal_contents_scale_, twin->raster_contents_scale_);
     // Ignore 0 scale in case CalculateContentsScale() has never been
     // called for active twin.
     if (twin_min_acceptable_scale != 0.0f) {
@@ skipping 957 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