Provide a std::vector compliant empty() method for WebVector.

third_party/WebKit/Source/core/testing/Internals.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  * Copyright (C) 2013 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 1702 matching lines @@
       }
     } while (updated);
   }
 }
 
 static void accumulateLayerRectList(PaintLayerCompositor* compositor,
                                     GraphicsLayer* graphicsLayer,
                                     LayerRectList* rects) {
   WebVector<blink::WebRect> layerRects =
       graphicsLayer->platformLayer()->touchEventHandlerRegion();
-  if (!layerRects.isEmpty()) {
+  if (!layerRects.empty()) {
     mergeRects(layerRects);
     String layerType;
     IntSize layerOffset;
     PaintLayer* paintLayer = findLayerForGraphicsLayer(
         compositor->rootLayer(), graphicsLayer, &layerOffset, &layerType);
     Node* node = paintLayer ? paintLayer->layoutObject().node() : 0;
     for (size_t i = 0; i < layerRects.size(); ++i) {
       if (!layerRects[i].isEmpty()) {
         rects->append(node, layerType, layerOffset.width(),
                       layerOffset.height(), ClientRect::create(layerRects[i]));
@@ skipping 1486 matching lines @@
 
 void Internals::crash() {
   CHECK(false) << "Intentional crash";
 }
 
 void Internals::setIsLowEndDevice(bool isLowEndDevice) {
   MemoryCoordinator::setIsLowEndDeviceForTesting(isLowEndDevice);
 }
 
 }  // namespace blink