Have pending and active tree use the same space for invalidations

cc/tiles/picture_layer_tiling.cc

Index: cc/tiles/picture_layer_tiling.cc
diff --git a/cc/tiles/picture_layer_tiling.cc b/cc/tiles/picture_layer_tiling.cc
index 9e79f4a40fa08517ff05fdd1002c4a511d773b6f..01beed6937045970d700af0c0b34e1f2203844bd 100644
--- a/cc/tiles/picture_layer_tiling.cc
+++ b/cc/tiles/picture_layer_tiling.cc
@@ -386,10 +386,15 @@ bool PictureLayerTiling::ShouldCreateTileAt(
   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