PlzNavigate: Invoke didStartProvisionalLoad() when the renderer initiates a navigation in startLoad(

chrome/renderer/chrome_render_frame_observer.h

 // 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.
 
 #ifndef CHROME_RENDERER_CHROME_RENDER_FRAME_OBSERVER_H_
 #define CHROME_RENDERER_CHROME_RENDER_FRAME_OBSERVER_H_
 
 #include "base/macros.h"
 #include "base/timer/timer.h"
 #include "chrome/common/prerender_types.h"
@@ skipping 16 matching lines @@
 class ChromeRenderFrameObserver : public content::RenderFrameObserver {
  public:
   explicit ChromeRenderFrameObserver(content::RenderFrame* render_frame);
   ~ChromeRenderFrameObserver() override;
 
  private:
   enum TextCaptureType { PRELIMINARY_CAPTURE, FINAL_CAPTURE };
 
   // RenderFrameObserver implementation.
   bool OnMessageReceived(const IPC::Message& message) override;
-  void DidStartProvisionalLoad() override;
+  void DidStartProvisionalLoad(blink::WebDataSource* data_source) override;
   void DidFinishLoad() override;
   void DidCommitProvisionalLoad(bool is_new_navigation,
                                 bool is_same_page_navigation) override;
   void DidMeaningfulLayout(blink::WebMeaningfulLayout layout_type) override;
   void OnDestruct() override;
 
   // IPC handlers
   void OnSetIsPrerendering(prerender::PrerenderMode mode);
   void OnRequestReloadImageForContextNode();
   void OnRequestThumbnailForContextNode(
@@ skipping 14 matching lines @@
                             base::TimeDelta delay);
 
   // Have the same lifetime as us.
   translate::TranslateHelper* translate_helper_;
   safe_browsing::PhishingClassifierDelegate* phishing_classifier_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeRenderFrameObserver);
 };
 
 #endif  // CHROME_RENDERER_CHROME_RENDER_FRAME_OBSERVER_H_