Change the display list interest rect size to 4000px instead of 8000px.

cc/playback/display_list_recording_source.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_list_recording_source.h"
 
 #include <algorithm>
 
 #include "cc/base/histograms.h"
 #include "cc/base/region.h"
 #include "cc/layers/content_layer_client.h"
 #include "cc/playback/display_item_list.h"
 #include "cc/playback/display_list_raster_source.h"
 #include "skia/ext/analysis_canvas.h"
 
 namespace {
 
 // Layout pixel buffer around the visible layer rect to record.  Any base
 // picture that intersects the visible layer rect expanded by this distance
 // will be recorded.
-const int kPixelDistanceToRecord = 8000;
+const int kPixelDistanceToRecord = 4000;
 
 // This is the distance, in layer space, by which the recorded viewport has to
 // change before causing a paint of the new content. For example, it means
 // that one has to scroll a very large page by 512 pixels before we will
 // re-record a new DisplayItemList for an updated recorded viewport.
 const int kMinimumDistanceBeforeUpdatingRecordedViewport = 512;
 
 #ifdef NDEBUG
 const bool kDefaultClearCanvasSetting = false;
 #else
@@ skipping 220 matching lines @@
 }
 
 void DisplayListRecordingSource::Clear() {
   recorded_viewport_ = gfx::Rect();
   display_list_ = NULL;
   painter_reported_memory_usage_ = 0;
   is_solid_color_ = false;
 }
 
 }  // namespace cc