Move visual rect unioning between paired items to cc::DisplayItemList.

cc/playback/display_item_list.cc

 // Copyright 2014 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/playback/display_item_list.h"
 
 #include <stddef.h>
 
 #include <string>
 
@@ skipping 146 matching lines @@
       picture_->playback(canvas, callback);
     } else {
       // Prefer to call |drawPicture()| on the canvas since it could place the
       // entire picture on the canvas instead of parsing the skia operations.
       canvas->drawPicture(picture_.get());
     }
     canvas->restore();
   }
 }
 
+void DisplayItemList::GrowCurrentBeginItemVisualRect(
+    const gfx::Rect& visual_rect) {
+  if (!inputs_.begin_item_indices.empty())
+    inputs_.visual_rects[inputs_.begin_item_indices.back()].Union(visual_rect);
+}
+
 void DisplayItemList::ProcessAppendedItem(const DisplayItem* item) {
   if (inputs_.settings.use_cached_picture) {
     DCHECK(recorder_);
     item->Raster(recorder_->getRecordingCanvas(), nullptr);
   }
   if (!retain_individual_display_items_) {
     inputs_.items.Clear();
   }
 }
 
@@ skipping 147 matching lines @@
 }
 
 void DisplayItemList::GetDiscardableImagesInRect(
     const gfx::Rect& rect,
     float raster_scale,
     std::vector<DrawImage>* images) {
   image_map_.GetDiscardableImagesInRect(rect, raster_scale, images);
 }
 
 }  // namespace cc