Delete unused WebViewBenchmarkSupport interface

Source/web/WebViewImpl.h

Index: Source/web/WebViewImpl.h
diff --git a/Source/web/WebViewImpl.h b/Source/web/WebViewImpl.h
index 9a2bbca93060023fc3fa86b12262a73b55fabc56..756e1ceafccfc6f776c742ca2331abd03f8f5987 100644
--- a/Source/web/WebViewImpl.h
+++ b/Source/web/WebViewImpl.h
@@ -44,7 +44,6 @@
 #include "WebInputEvent.h"
 #include "WebNavigationPolicy.h"
 #include "WebView.h"
-#include "WebViewBenchmarkSupportImpl.h"
 #include "core/page/PagePopupDriver.h"
 #include "core/page/PageScaleConstraintsSet.h"
 #include "core/platform/Timer.h"
@@ -121,7 +120,6 @@ class WebPagePopupImpl;
 class WebPrerendererClient;
 class WebSettingsImpl;
 class WebTouchEvent;
-class WebViewBenchmarkSupport;
 class FullscreenController;
 
 class WebViewImpl : public WebView
@@ -311,7 +309,6 @@ public:
     virtual void addPageOverlay(WebPageOverlay*, int /* zOrder */);
     virtual void removePageOverlay(WebPageOverlay*);
     virtual void transferActiveWheelFlingAnimation(const WebActiveWheelFlingParameters&);
-    virtual WebViewBenchmarkSupport* benchmarkSupport();
     virtual void setShowPaintRects(bool);
     virtual void setShowDebugBorders(bool);
     virtual void setShowFPSCounter(bool);
@@ -793,8 +790,6 @@ private:
     // If set, the (plugin) node which has mouse capture.
     RefPtr<WebCore::Node> m_mouseCaptureNode;
 
-    WebViewBenchmarkSupportImpl m_benchmarkSupport;
-
     WebCore::IntRect m_rootLayerScrollDamage;
     WebLayerTreeView* m_layerTreeView;
     WebLayer* m_rootLayer;