cc: Make PaintedScrollbarLayer not use ContentsScalingLayer

cc/test/layer_test_common.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/test/layer_test_common.h"
 
 #include "cc/base/math_util.h"
 #include "cc/base/region.h"
 #include "cc/layers/append_quads_data.h"
 #include "cc/quads/draw_quad.h"
@@ skipping 57 matching lines @@
                                              size_t* partially_occluded_count) {
   // No quad should exist if it's fully occluded.
   for (const auto& quad : quads) {
     gfx::Rect target_visible_rect = MathUtil::MapEnclosingClippedRect(
         quad->quadTransform(), quad->visible_rect);
     EXPECT_FALSE(occluded.Contains(target_visible_rect));
   }
 
   // Quads that are fully occluded on one axis only should be shrunken.
   for (const auto& quad : quads) {
-    DCHECK(quad->quadTransform().IsIdentityOrIntegerTranslation());
+    DCHECK(quad->quadTransform().IsIdentityOrIntegerTranslation())
+        << quad->quadTransform().ToString();
     gfx::Rect target_rect =
         MathUtil::MapEnclosingClippedRect(quad->quadTransform(), quad->rect);
     gfx::Rect target_visible_rect = MathUtil::MapEnclosingClippedRect(
         quad->quadTransform(), quad->visible_rect);
 
     bool fully_occluded_horizontal = target_rect.x() >= occluded.x() &&
                                      target_rect.right() <= occluded.right();
     bool fully_occluded_vertical = target_rect.y() >= occluded.y() &&
                                    target_rect.bottom() <= occluded.bottom();
     bool should_be_occluded =
@@ skipping 73 matching lines @@
   render_pass_->shared_quad_state_list.clear();
   occlusion_tracker_.set_occluded_target_rect_for_contributing_surface(
       occluded);
   bool for_replica = false;
   RenderPassId id(1, 1);
   surface_impl->AppendQuads(
       render_pass_.get(), occlusion_tracker_, &data, for_replica, id);
 }
 
 }  // namespace cc