Add UMA to count the number of Google CAPTCHA pages shown and solved by users.

components/page_load_metrics/browser/metrics_web_contents_observer.h

 // Copyright 2015 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 COMPONENTS_PAGE_LOAD_METRICS_BROWSER_PAGE_LOAD_METRICS_WEB_CONTENTS_OBSERVER_H_
 #define COMPONENTS_PAGE_LOAD_METRICS_BROWSER_PAGE_LOAD_METRICS_WEB_CONTENTS_OBSERVER_H_
 
 #include "base/containers/scoped_ptr_map.h"
 #include "base/macros.h"
 #include "base/observer_list.h"
@@ skipping 179 matching lines @@
 // MetricsWebContentsObserver manages a set of provisional PageLoadTrackers, as
 // well as a committed PageLoadTracker.
 class PageLoadTracker {
  public:
   // Caller must guarantee that the observers and embedder_interface pointers
   // outlives this class.
   PageLoadTracker(bool in_foreground,
                   PageLoadMetricsEmbedderInterface* embedder_interface,
                   base::ObserverList<PageLoadMetricsObserver, true>* observers);
   ~PageLoadTracker();
+  void Redirect(content::NavigationHandle* navigation_handle);
   void Commit(content::NavigationHandle* navigation_handle);
   void WebContentsHidden();
   void WebContentsShown();
 
   // Returns true if the timing was successfully updated.
   bool UpdateTiming(const PageLoadTiming& timing);
   void RecordProvisionalEvent(ProvisionalLoadEvent event);
   void RecordCommittedEvent(CommittedLoadEvent event, bool backgrounded);
   bool HasBackgrounded();
 
@@ skipping 48 matching lines @@
   void AddObserver(PageLoadMetricsObserver* observer) override;
   void RemoveObserver(PageLoadMetricsObserver* observer) override;
 
   // content::WebContentsObserver implementation:
   bool OnMessageReceived(const IPC::Message& message,
                          content::RenderFrameHost* render_frame_host) override;
   void DidStartNavigation(
       content::NavigationHandle* navigation_handle) override;
   void DidFinishNavigation(
       content::NavigationHandle* navigation_handle) override;
+  void DidRedirectNavigation(
+      content::NavigationHandle* navigation_handle) override;
 
   void WasShown() override;
   void WasHidden() override;
 
   void RenderProcessGone(base::TerminationStatus status) override;
 
  private:
   friend class content::WebContentsUserData<MetricsWebContentsObserver>;
 
   void OnTimingUpdated(content::RenderFrameHost*, const PageLoadTiming& timing);
@@ skipping 11 matching lines @@
 
   scoped_ptr<PageLoadMetricsEmbedderInterface> embedder_interface_;
   base::ObserverList<PageLoadMetricsObserver, true> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(MetricsWebContentsObserver);
 };
 
 }  // namespace page_load_metrics
 
 #endif  // COMPONENTS_PAGE_LOAD_METRICS_BROWSER_PAGE_LOAD_METRICS_WEB_CONTENTS_OBSERVER_H_