Have the unload event execute in background on cross-site navigations

content/public/browser/render_process_host.h

Index: content/public/browser/render_process_host.h
diff --git a/content/public/browser/render_process_host.h b/content/public/browser/render_process_host.h
index 436108a398bd7eef071a9c1001d6ea0d2d75804d..3f93bcd8717ef835fcfc830bb023d60cc343c9c0 100644
--- a/content/public/browser/render_process_host.h
+++ b/content/public/browser/render_process_host.h
@@ -29,6 +29,7 @@ class BrowserMessageFilter;
 class RenderProcessHostObserver;
 class RenderWidgetHost;
 class StoragePartition;
+struct GlobalRequestID;
 
 typedef base::Thread* (*RendererMainThreadFactoryFunction)(
     const std::string& id);
@@ -217,6 +218,10 @@ class CONTENT_EXPORT RenderProcessHost : public IPC::Sender,
   virtual void DisableAecDump() = 0;
 #endif
 
+  // Tells the ResourceDispatcherHost to resume a deferred navigation without
+  // transferring it to a new renderer process.
+  virtual void ResumeDeferredNavigation(const GlobalRequestID& request_id) = 0;

[nasko, 2014/01/23 23:34:58]

Why is this a public method now? I don't see anyone outside of content using it
in your patch.

[clamy, 2014/01/24 17:01:54]

The method used to be in RenderProcessHostImpl, where it was public. It is
called in RenderFrameHostManager::SwappedOut where we static_cast a
RenderProcessHost into a RenderProcessHostImpl. In one of the unit_tests, we use
MockRenderProcessHost and happen, because of the patch, to hit this particular
cast when we previously did not (because the call to delegate_->SwappedOut(this)
in the RVH moved from OnSwappedOut to SwapOut). Since MockRenderProcessHost is
not derived from RenderProcessHostImpl, this was causing problems, and I had to
move this specific method to the parent class of RenderProcessHostImpl and
MockRenderProcessHost, that is here, in RenderProcessHost.

[jam, 2014/02/04 23:42:37]

This is an unfortunate side effect of having the public interface of
RenderProcessHostImpl be the same base class for the mock version. I did this
because I didn't want to create yet another base class for RPH when we added the
content api. if it's just one test, and you can find a way to rewrite it as a
browser test (where all implementations will be RenderProcessHostImpl), that
would be great. if not, ok.

[clamy, 2014/02/05 14:21:42]

I think I will leave it as it is now, as this is already quite a big change, and
am not really sure about rewriting the unit test into a browser test.

+
   // Static management functions -----------------------------------------------
 
   // Flag to run the renderer in process.  This is primarily