cc: Fix tree activation when invisible layers exist.

cc/picture_layer_tiling_unittest.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/picture_layer_tiling.h"
 
 #include "cc/test/fake_picture_layer_tiling_client.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/gfx/size_conversions.h"
 
@@ skipping 101 matching lines @@
   VerifyTilesExactlyCoverRect(2.0f, gfx::Rect(512, 365, 253, 182));
 
   float scale = 6.7f;
   gfx::Size bounds(800, 600);
   gfx::Rect full_rect(gfx::ToCeiledSize(gfx::ScaleSize(bounds, scale)));
   Initialize(gfx::Size(256, 512), 5.2f, bounds);
   VerifyTilesExactlyCoverRect(scale, full_rect);
   VerifyTilesExactlyCoverRect(scale, gfx::Rect(2014, 1579, 867, 1033));
 }
 
+TEST_F(PictureLayerTilingIteratorTest, IteratorEmptyRect) {
+  Initialize(gfx::Size(100, 100), 1, gfx::Size(800, 600));
+
+  gfx::Rect empty;
+  PictureLayerTiling::Iterator iter(tiling_.get(), 1, empty);
+  EXPECT_FALSE(iter);
+}
+
 }  // namespace
 }  // namespace cc