Remove WebContents::InsertCSS since it is unused

content/browser/web_contents/web_contents_impl.cc

 // 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.
 
 #include "content/browser/web_contents/web_contents_impl.h"
 
 #include <stddef.h>
 
 #include <cmath>
 #include <utility>
@@ skipping 3091 matching lines @@
   // See if a top level browser plugin handles the stop finding request first.
   // TODO(paulmeyer): Remove this after find-in-page works across GuestViews.
   if (browser_plugin_embedder_ &&
       browser_plugin_embedder_->StopFinding(action)) {
     return;
   }
 
   GetOrCreateFindRequestManager()->StopFinding(action);
 }
 
-void WebContentsImpl::InsertCSS(const std::string& css) {
-  GetMainFrame()->Send(new FrameMsg_CSSInsertRequest(
-      GetMainFrame()->GetRoutingID(), css));
-}
-
 bool WebContentsImpl::WasRecentlyAudible() {
   return audio_stream_monitor_.WasRecentlyAudible() ||
          (browser_plugin_embedder_ &&
           browser_plugin_embedder_->WereAnyGuestsRecentlyAudible());
 }
 
 void WebContentsImpl::GetManifest(const GetManifestCallback& callback) {
   manifest_manager_host_->GetManifest(GetMainFrame(), callback);
 }
 
@@ skipping 2043 matching lines @@
   for (RenderViewHost* render_view_host : render_view_host_set)
     render_view_host->OnWebkitPreferencesChanged();
 }
 
 void WebContentsImpl::SetJavaScriptDialogManagerForTesting(
     JavaScriptDialogManager* dialog_manager) {
   dialog_manager_ = dialog_manager;
 }
 
 }  // namespace content