cc: Fix impl-side painting flashing due to missing tiles

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 "base/debug/trace_event.h"
@@ skipping 277 matching lines @@
     const gfx::RectF& visible_layer_rect,
     gfx::Size last_layer_bounds,
     gfx::Size current_layer_bounds,
     float last_layer_contents_scale,
     float current_layer_contents_scale,
     const gfx::Transform& last_screen_transform,
     const gfx::Transform& current_screen_transform,
     double current_frame_time_in_seconds,
     bool store_screen_space_quads_on_tiles,
     size_t max_tiles_for_interest_area) {
-  if (ContentRect().IsEmpty())
+  if (!NeedsUpdateForFrameAtTime(current_frame_time_in_seconds)) {
+    // This should never be zero for the purposes of has_ever_been_updated().
+    DCHECK_NE(current_frame_time_in_seconds, 0.0);
     return;
-  if (!NeedsUpdateForFrameAtTime(current_frame_time_in_seconds))
+  }
+  if (ContentRect().IsEmpty()) {
+    last_impl_frame_time_in_seconds_ = current_frame_time_in_seconds;

[danakj, 2013/05/03 01:11:22]

Oh, word.

     return;
+  }
 
   gfx::Rect viewport_in_content_space =
       gfx::ToEnclosingRect(gfx::ScaleRect(viewport_in_layer_space,
                                           contents_scale_));
   gfx::Rect visible_content_rect =
       gfx::ToEnclosingRect(gfx::ScaleRect(visible_layer_rect,
                                           contents_scale_));
 
   gfx::Size tile_size = tiling_data_.max_texture_size();
   int64 interest_rect_area =
@@ skipping 290 matching lines @@
 
     // If our delta is less then our event distance, we're done.
     if (delta < event.distance)
       break;
   }
 
   return gfx::Rect(origin_x, origin_y, width, height);
 }
 
 }  // namespace cc