Remove unusued WebFrameClient::willRequestResource and WebCachedURLRequest

public/web/WebFrameClient.h

Index: public/web/WebFrameClient.h
diff --git a/public/web/WebFrameClient.h b/public/web/WebFrameClient.h
index db5910bd65b2784b6db15515b85e8c451caca285..0d27fbfc407557f8c38c923c735b5ee8fba4db3b 100644
--- a/public/web/WebFrameClient.h
+++ b/public/web/WebFrameClient.h
@@ -61,7 +61,6 @@ class WebApplicationCacheHost;
 class WebApplicationCacheHostClient;
 class WebAppBannerClient;
 class WebBluetooth;
-class WebCachedURLRequest;
 class WebColorChooser;
 class WebColorChooserClient;
 class WebContentDecryptionModule;
@@ -412,9 +411,6 @@ public:
 
     // Low-level resource notifications ------------------------------------
 
-    // An element will request a resource.
-    virtual void willRequestResource(WebLocalFrame*, const WebCachedURLRequest&) { }
-
     // A request is about to be sent out, and the client may modify it.  Request
     // is writable, and changes to the URL, for example, will change the request
     // made.  If this request is the result of a redirect, then redirectResponse