Remove WebContents::InsertCSS since it is unused

content/public/browser/web_contents.h

 // Copyright (c) 2012 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.
 
 #ifndef CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_H_
 #define CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_H_
 
 #include <stdint.h>
 
 #include <set>
@@ skipping 673 matching lines @@
 
   // Finds text on a page. |search_text| should not be empty.
   virtual void Find(int request_id,
                     const base::string16& search_text,
                     const blink::WebFindOptions& options) = 0;
 
   // Notifies the renderer that the user has closed the FindInPage window
   // (and what action to take regarding the selection).
   virtual void StopFinding(StopFindAction action) = 0;
 
-  // Requests the renderer to insert CSS into the main frame's document.
-  virtual void InsertCSS(const std::string& css) = 0;
-
   // Returns true if audio has recently been audible from the WebContents.
   virtual bool WasRecentlyAudible() = 0;
 
   // The callback invoked when the renderer responds to a request for the main
   // frame document's manifest. The url will be empty if the document specifies
   // no manifest, and the manifest will be empty if any other failures occurred.
   typedef base::Callback<void(const GURL&, const Manifest&)>
       GetManifestCallback;
 
   // Requests the manifest URL and the Manifest of the main frame's document.
@@ skipping 48 matching lines @@
 
  private:
   // This interface should only be implemented inside content.
   friend class WebContentsImpl;
   WebContents() {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_H_