PlzNavigate: Speculatively spawns a renderer process for navigations.

content/public/test/web_contents_tester.h

 // 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.
 
 #ifndef CONTENT_PUBLIC_TEST_WEB_CONTENTS_TESTER_H_
 #define CONTENT_PUBLIC_TEST_WEB_CONTENTS_TESTER_H_
 
 #include "ui/base/page_transition_types.h"
 
 class GURL;
@@ skipping 46 matching lines @@
       SiteInstance* instance);
 
   // Simulates the appropriate RenderView (pending if any, current otherwise)
   // sending a navigate notification for the NavigationController pending entry.
   virtual void CommitPendingNavigation() = 0;
 
   // Gets the pending RenderFrameHost, if any, for the main frame. For the
   // current RenderFrameHost of the main frame, use WebContents::GetMainFrame().
   virtual RenderFrameHost* GetPendingMainFrame() const = 0;
 
+  // Gets the speculative RenderFrameHost, if any, for the main frame.

[clamy, 2014/12/19 13:35:57]

Please preface this with a PlzNavigate comment. Also, we would need a method
that would return either the pending RFH in current navigation or the
speculative one in PlzNavigate to use in unit tests (to replace
GetPendingMainFrame in many of them). Maybe it can be called GetNextMainFrame,
or GetFutureMainFrame.

And I'm not sure we currently need to expose both these methods to the public
API.

[nasko, 2014/12/20 00:09:09]

This definitely should not be exposed through public API. This is totally an
internal optimization in content/ and shouldn't be known outside of it (even
outside of RFHM if we want to be precise).

[carlosk, 2014/12/29 16:40:16]

I added it to the public API because there is already one for the pending RFH.
It's now removed from it.

Given the previous request from clamy@ I kept it in the private API, added the
pending-speculative shared getter but turned both into private methods.

+  virtual RenderFrameHost* GetSpeculativeMainFrame() const = 0;
+
   // Creates a pending navigation to the given URL with the default parameters
   // and then commits the load with a page ID one larger than any seen. This
   // emulates what happens on a new navigation.
   virtual void NavigateAndCommit(const GURL& url) = 0;
 
   // Sets the loading state to the given value.
   virtual void TestSetIsLoading(bool value) = 0;
 
   // Simulates the current RVH notifying that it has unloaded so that the
   // pending RVH navigation can proceed.
@@ skipping 12 matching lines @@
       const Referrer& referrer,
       ui::PageTransition transition) = 0;
 
   // Promote ComputeWebkitPrefs to public.
   virtual WebPreferences TestComputeWebkitPrefs() = 0;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_TEST_WEB_CONTENTS_TESTER_H_