Fix scrollbar overflow with ScaleToEnclosingRectSafe

cc/layers/painted_scrollbar_layer.cc

 // Copyright 2013 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/layers/painted_scrollbar_layer.h"
 
 #include <algorithm>
 
 #include "base/auto_reset.h"
 #include "cc/base/math_util.h"
@@ skipping 115 matching lines @@
     thumb_resource_ = nullptr;
   }
 
   Layer::SetLayerTreeHost(host);
 }
 
 gfx::Rect PaintedScrollbarLayer::ScrollbarLayerRectToContentRect(
     const gfx::Rect& layer_rect) const {
   // Don't intersect with the bounds as in LayerRectToContentRect() because
   // layer_rect here might be in coordinates of the containing layer.
-  gfx::Rect expanded_rect = gfx::ScaleToEnclosingRect(
+  gfx::Rect expanded_rect = gfx::ScaleToEnclosingRectSafe(
       layer_rect, internal_contents_scale_, internal_contents_scale_);
   // We should never return a rect bigger than the content bounds.
   gfx::Size clamped_size = expanded_rect.size();
   clamped_size.SetToMin(internal_content_bounds_);
   expanded_rect.set_size(clamped_size);
   return expanded_rect;
 }
 
 gfx::Rect PaintedScrollbarLayer::OriginThumbRect() const {
   gfx::Size thumb_size;
@@ skipping 136 matching lines @@
 
   scrollbar_->PaintPart(&skcanvas, part, layer_rect);
   // Make sure that the pixels are no longer mutable to unavoid unnecessary
   // allocation and copying.
   skbitmap.setImmutable();
 
   return UIResourceBitmap(skbitmap);
 }
 
 }  // namespace cc