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

chrome/renderer/chrome_render_frame_observer.cc

Index: chrome/renderer/chrome_render_frame_observer.cc
diff --git a/chrome/renderer/chrome_render_frame_observer.cc b/chrome/renderer/chrome_render_frame_observer.cc
index 74b09d172cb23f879fe212d712026186e22d1409..ce6d9d01c9a08f47d19a7603856142b0a2c70a6d 100644
--- a/chrome/renderer/chrome_render_frame_observer.cc
+++ b/chrome/renderer/chrome_render_frame_observer.cc
@@ -161,8 +161,9 @@ bool ChromeRenderFrameObserver::OnMessageReceived(const IPC::Message& message) {
   return handled;
 }
 
-void ChromeRenderFrameObserver::OnSetIsPrerendering(bool is_prerendering) {
-  if (is_prerendering) {
+void ChromeRenderFrameObserver::OnSetIsPrerendering(
+    prerender::PrerenderMode mode) {
+  if (mode == prerender::FULL_PRERENDER) {

[mattcary, 2016/07/27 11:31:54]

Should this be mode != NO_PRERENDER? I thought we would need a prerender helper
for prefetch as well.

[droger, 2016/07/27 13:16:55]

Good point, done.

     // 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