Prerendered pages are swapped in at browser::Navigate time.

chrome/browser/prerender/prerender_contents.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 "chrome/browser/prerender/prerender_contents.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/process_util.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/history/history_tab_helper.h"
 #include "chrome/browser/history/history_types.h"
 #include "chrome/browser/prerender/prerender_final_status.h"
 #include "chrome/browser/prerender/prerender_manager.h"
 #include "chrome/browser/prerender/prerender_render_view_host_observer.h"
 #include "chrome/browser/prerender/prerender_tracker.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_list.h"
 #include "chrome/browser/ui/tab_contents/tab_contents_wrapper.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "chrome/common/icon_messages.h"
-#include "chrome/common/render_messages.h"
+#include "chrome/common/prerender_messages.h"
 #include "chrome/common/url_constants.h"
 #include "content/browser/in_process_webkit/session_storage_namespace.h"
 #include "content/browser/renderer_host/render_view_host.h"
 #include "content/browser/renderer_host/resource_request_details.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_delegate.h"
 #include "content/public/browser/web_contents_view.h"
 #include "ui/gfx/rect.h"
@@ skipping 198 matching lines @@
 
 bool PrerenderContents::Init() {
   return AddAliasURL(prerender_url_);
 }
 
 // static
 PrerenderContents::Factory* PrerenderContents::CreateFactory() {
   return new PrerenderContentsFactoryImpl();
 }
 
+void BroadcastPrerender(const GURL& url, bool is_add) {
+  content::RenderProcessHost::iterator host_it =
+      content::RenderProcessHost::AllHostsIterator();
+  while (!host_it.IsAtEnd()) {
+    content::RenderProcessHost* host = host_it.GetCurrentValue();
+    host_it.Advance();
+    if (!host)
+      continue;
+    // TODO(cbentzel): Need to filter to the current profile only.

[dominich, 2012/02/28 16:21:00]

Should you also filter to the RPH that was the source of the prerender? That
should be the only one that needs to know about it.

[cbentzel, 2012/02/29 18:16:13]

I am limiting to that now, per your comment as well as creis's.

There may be some prerenders we are dropping on the floor here as a result, but
my guess it it's pretty low. However, this may change if we start doing some
other triggers for prerender such as top sites or co-visited domains.

+    IPC::Message* message = NULL;

[dominich, 2012/02/28 16:21:00]

IPC::Message* message = is_add ? new PrerenderMsg_AddPrerenderURL(url) :
                                 new PrerenderMsg_RemovePrerenderURL(url);

[cbentzel, 2012/02/29 18:16:13]

This doesn't work because then the operands of the ternary operator are
different types. I could do a static_cast to IPC::Message, but then it's verbose
and doesn't buy much.

+    if (is_add) {
+      message = new PrerenderMsg_AddPrerenderURL(url);
+    } else {
+      message = new PrerenderMsg_RemovePrerenderURL(url);
+    }
+    // TODO(cbentzel): Make sure that sending a message doesn't
+    // adjust the iterator.
+    host->Send(message);
+  }
+}
+
 void PrerenderContents::StartPrerendering(
     const RenderViewHost* source_render_view_host,
     SessionStorageNamespace* session_storage_namespace) {
   DCHECK(profile_ != NULL);
   DCHECK(!prerendering_has_started_);
   DCHECK(prerender_contents_.get() == NULL);
 
   prerendering_has_started_ = true;
+  BroadcastPrerender(prerender_url_, true);
+
   WebContents* new_contents = WebContents::Create(
       profile_, NULL, MSG_ROUTING_NONE, NULL, session_storage_namespace);
   prerender_contents_.reset(new TabContentsWrapper(new_contents));
   content::WebContentsObserver::Observe(new_contents);
 
   gfx::Rect tab_bounds;
   if (source_render_view_host) {
     DCHECK(source_render_view_host->view() != NULL);
     WebContents* source_wc =
         source_render_view_host->delegate()->GetAsWebContents();
@@ skipping 150 matching lines @@
 
         content::Details<RenderViewHost> new_render_view_host(details);
         OnRenderViewHostCreated(new_render_view_host.ptr());
 
         // When a new RenderView is created for a prerendering TabContents,
         // tell the new RenderView it's being used for prerendering before any
         // navigations occur.  Note that this is always triggered before the
         // first navigation, so there's no need to send the message just after
         // the TabContents is created.
         new_render_view_host->Send(
-            new ChromeViewMsg_SetIsPrerendering(
+            new PrerenderMsg_SetIsPrerendering(
                 new_render_view_host->routing_id(),
                 true));
 
         // Make sure the size of the RenderViewHost has been passed to the new
         // RenderView.  Otherwise, the size may not be sent until the
         // RenderViewReady event makes it from the render process to the UI
         // thread of the browser process.  When the RenderView receives its
         // size, is also sets itself to be visible, which would then break the
         // visibility API.
         new_render_view_host->WasResized();
@@ skipping 104 matching lines @@
 bool PrerenderContents::ShouldSuppressDialogs() {
   // Always suppress JavaScript messages if they're triggered by a page being
   // prerendered.
   // We still want to show the user the message when they navigate to this
   // page, so cancel this prerender.
   Destroy(FINAL_STATUS_JAVASCRIPT_ALERT);
   return true;
 }
 
 void PrerenderContents::Destroy(FinalStatus final_status) {
+  BroadcastPrerender(prerender_url_, false);
   if (prerendering_has_been_cancelled_)
     return;
 
   if (child_id_ != -1 && route_id_ != -1) {
     // Cancel the prerender in the PrerenderTracker.  This is needed
     // because destroy may be called directly from the UI thread without calling
     // TryCancel().  This is difficult to completely avoid, since prerendering
     // can be cancelled before a RenderView is created.
     bool is_cancelled = prerender_tracker_->TryCancel(
         child_id_, route_id_, final_status);
@@ skipping 94 matching lines @@
 bool PrerenderContents::IsCrossSiteNavigationPending() const {
   if (!prerender_contents_.get() || !prerender_contents_->web_contents())
     return false;
   const WebContents* web_contents = prerender_contents_->web_contents();
   return (web_contents->GetSiteInstance() !=
           web_contents->GetPendingSiteInstance());
 }
 
 
 }  // namespace prerender