Use the stateless GC::fillRect variant when possible.

Source/core/paint/LayerPainter.cpp

 // Copyright 2014 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 "config.h"
 #include "core/paint/LayerPainter.h"
 
 #include "core/frame/Settings.h"
 #include "core/page/Page.h"
 #include "core/rendering/ClipPathOperation.h"
@@ skipping 120 matching lines @@
         context->clip(clipRect);
 
         if (m_renderLayer.paintsWithBlendMode())
             context->setCompositeOperation(context->compositeOperation(), m_renderLayer.renderer()->style()->blendMode());
 
         context->beginTransparencyLayer(m_renderLayer.renderer()->opacity());
 
         if (m_renderLayer.paintsWithBlendMode())
             context->setCompositeOperation(context->compositeOperation(), WebBlendModeNormal);
 #ifdef REVEAL_TRANSPARENCY_LAYERS
-        context->setFillColor(Color(0.0f, 0.0f, 0.5f, 0.2f));
-        context->fillRect(clipRect);
+        context->fillRect(clipRect, Color(0.0f, 0.0f, 0.5f, 0.2f));
 #endif
     }
 }
 
 void LayerPainter::paintLayerContentsAndReflection(GraphicsContext* context, const LayerPaintingInfo& paintingInfo, PaintLayerFlags paintFlags)
 {
     ASSERT(m_renderLayer.isSelfPaintingLayer() || m_renderLayer.hasSelfPaintingLayerDescendant());
 
     PaintLayerFlags localPaintFlags = paintFlags & ~(PaintLayerAppliedTransform);
 
@@ skipping 723 matching lines @@
         if (needsToClip(paintingInfo, clipRect)) {
             clipRecorder = adoptPtr(new ClipRecorder(m_renderLayer.parent(), context, ClipDisplayItem::LayerFragmentParent, clipRect));
             LayerPainter(*m_renderLayer.parent()).applyRoundedRectClips(paintingInfo, context, clipRect, paintFlags, *clipRecorder, DoNotIncludeSelfForBorderRadius); // Child clipping mask painting will handle clipping to self.
         }
 
         paintLayerByApplyingTransform(context, paintingInfo, paintFlags, fragment.paginationOffset);
     }
 }
 
 } // namespace blink