Have pending and active tree use the same space for invalidations

cc/tiles/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/tiles/picture_layer_tiling.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <cmath>
@@ skipping 368 matching lines @@
     return true;
 
   // If the active tree can't create a tile, because of its raster source, then
   // the pending tree should create one.
   if (!active_twin->raster_source()->CoversRect(info.enclosing_layer_rect))
     return true;
 
   const Region* layer_invalidation = client_->GetPendingInvalidation();
 
   // If this tile is invalidated, then the pending tree should create one.
-  if (layer_invalidation &&
-      layer_invalidation->Intersects(info.enclosing_layer_rect))
-    return true;
-
+  // Do the intersection test in content space to match the corresponding check
+  // on the active tree and avoid floating point inconsistencies.
+  for (Region::Iterator iter(*layer_invalidation); iter.has_rect();
+       iter.next()) {
+    gfx::Rect invalid_content_rect =
+        gfx::ScaleToEnclosingRect(iter.rect(), contents_scale_);
+    if (invalid_content_rect.Intersects(info.content_rect))
+      return true;
+  }
   // If the active tree doesn't have a tile here, but it's in the pending tree's
   // visible rect, then the pending tree should create a tile. This can happen
   // if the pending visible rect is outside of the active tree's live tiles
   // rect. In those situations, we need to block activation until we're ready to
   // display content, which will have to come from the pending tree.
   if (!active_twin->TileAt(i, j) &&
       current_visible_rect_.Intersects(info.content_rect))
     return true;
 
   // In all other cases, the pending tree doesn't need to create a tile.
@@ skipping 631 matching lines @@
 size_t PictureLayerTiling::GPUMemoryUsageInBytes() const {
   size_t amount = 0;
   for (TileMap::const_iterator it = tiles_.begin(); it != tiles_.end(); ++it) {
     const Tile* tile = it->second.get();
     amount += tile->GPUMemoryUsageInBytes();
   }
   return amount;
 }
 
 }  // namespace cc