cc: Don't DCHECK for layers with non-invertible transforms.

cc/resources/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/resources/picture_layer_tiling.h"
 
 #include "cc/test/fake_picture_layer_tiling_client.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/gfx/rect_conversions.h"
 #include "ui/gfx/size_conversions.h"
@@ skipping 340 matching lines @@
 
 TEST(PictureLayerTilingTest, ExpandRectOutOfBounds) {
   gfx::Rect in(40, 50, 100, 200);
   gfx::Rect bounds(0, 0, 10, 10);
   int64 target_area = 400 * 400;
   gfx::Rect out = PictureLayerTiling::ExpandRectEquallyToAreaBoundedBy(
       in, target_area, bounds);
   EXPECT_TRUE(out.IsEmpty());
 }
 
+TEST(PictureLayerTilingTest, EmptyStartingRect) {

[enne (OOO), 2013/04/09 02:08:38]

WTB unit test that makes sure this layer also has visible resources ready.

[danakj, 2013/04/09 02:42:17]

OK will do!

+  // If a layer has a non-invertible transform, then the starting rect
+  // for the layer would be empty.
+  gfx::Rect in(40, 40, 0, 0);
+  gfx::Rect bounds(0, 0, 10, 10);
+  int64 target_area = 400 * 400;
+  gfx::Rect out = PictureLayerTiling::ExpandRectEquallyToAreaBoundedBy(
+      in, target_area, bounds);
+  EXPECT_TRUE(out.IsEmpty());
+}
+
 }  // namespace
 }  // namespace cc