[Prerender] Change IPC from bool to enum for more prerender modes

chrome/renderer/chrome_render_frame_observer.cc

 // Copyright 2013 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 "chrome/renderer/chrome_render_frame_observer.h"
 
 #include <stddef.h>
 #include <string.h>
 
 #include <limits>
@@ skipping 140 matching lines @@
                         OnPrintNodeUnderContextMenu)
 #endif
     IPC_MESSAGE_HANDLER(ChromeViewMsg_AppBannerPromptRequest,
                         OnAppBannerPromptRequest)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
 
   return handled;
 }
 
-void ChromeRenderFrameObserver::OnSetIsPrerendering(bool is_prerendering) {
-  if (is_prerendering) {
+void ChromeRenderFrameObserver::OnSetIsPrerendering(
+    prerender::PrerenderMode mode) {
+  if (mode != prerender::NO_PRERENDER) {
     // If the PrerenderHelper for this frame already exists, don't create it. It
     // can already be created for subframes during handling of
     // RenderFrameCreated, if the parent frame was prerendering at time of
     // subframe creation.
     if (prerender::PrerenderHelper::Get(render_frame()))
       return;
 
     // The PrerenderHelper will destroy itself either after recording histograms
     // or on destruction of the RenderView.
     new prerender::PrerenderHelper(render_frame());
@@ skipping 191 matching lines @@
       CapturePageText(FINAL_CAPTURE);
       break;
     default:
       break;
   }
 }
 
 void ChromeRenderFrameObserver::OnDestruct() {
   delete this;
 }