Revert of Break page load metrics test dependency on IPC.

chrome/browser/page_load_metrics/metrics_web_contents_observer.h

Index: chrome/browser/page_load_metrics/metrics_web_contents_observer.h
diff --git a/chrome/browser/page_load_metrics/metrics_web_contents_observer.h b/chrome/browser/page_load_metrics/metrics_web_contents_observer.h
index a2e14507ed3b7b3b1b7b21cb59ff839f0c0e66c4..309685452a9246bb1e0ff5d4d38f2e13721194b1 100644
--- a/chrome/browser/page_load_metrics/metrics_web_contents_observer.h
+++ b/chrome/browser/page_load_metrics/metrics_web_contents_observer.h
@@ -10,7 +10,6 @@
 #include <vector>
 
 #include "base/macros.h"
-#include "base/observer_list.h"
 #include "base/time/time.h"
 #include "chrome/browser/page_load_metrics/page_load_metrics_observer.h"
 #include "chrome/common/page_load_metrics/page_load_timing.h"
@@ -44,27 +43,6 @@
       public content::WebContentsUserData<MetricsWebContentsObserver>,
       public content::RenderWidgetHost::InputEventObserver {
  public:
-  // TestingObserver allows tests to observe MetricsWebContentsObserver state
-  // changes. Tests may use TestingObserver to wait until certain state changes,
-  // such as the arrivial of PageLoadTiming messages from the render process,
-  // have been observed.
-  class TestingObserver {
-   public:
-    explicit TestingObserver(content::WebContents* web_contents);
-    virtual ~TestingObserver();
-
-    void OnGoingAway();
-
-    // Invoked when a new PageLoadTiming update has been received and processed.
-    virtual void OnTimingUpdated(const PageLoadTiming& timing,
-                                 const PageLoadMetadata& metadata) {}
-
-   private:
-    page_load_metrics::MetricsWebContentsObserver* observer_;
-
-    DISALLOW_COPY_AND_ASSIGN(TestingObserver);
-  };
-
   // Note that the returned metrics is owned by the web contents.
   static MetricsWebContentsObserver* CreateForWebContents(
       content::WebContents* web_contents,
@@ -125,15 +103,6 @@
   // This getter function is required for testing.
   const PageLoadExtraInfo GetPageLoadExtraInfoForCommittedLoad();
 
-  // Register / unregister TestingObservers. Should only be called from tests.
-  void AddTestingObserver(TestingObserver* observer);
-  void RemoveTestingObserver(TestingObserver* observer);
-
-  // public only for testing
-  void OnTimingUpdated(content::RenderFrameHost* render_frame_host,
-                       const PageLoadTiming& timing,
-                       const PageLoadMetadata& metadata);
-
  private:
   friend class content::WebContentsUserData<MetricsWebContentsObserver>;
 
@@ -174,6 +143,10 @@
       content::NavigationHandle* new_navigation,
       UserInitiatedInfo user_initiated_info);
 
+  void OnTimingUpdated(content::RenderFrameHost*,
+                       const PageLoadTiming& timing,
+                       const PageLoadMetadata& metadata);
+
   bool ShouldTrackNavigation(
       content::NavigationHandle* navigation_handle) const;
 
@@ -203,8 +176,6 @@
   // Has the MWCO observed at least one navigation?
   bool has_navigated_;
 
-  base::ObserverList<TestingObserver> testing_observers_;
-
   DISALLOW_COPY_AND_ASSIGN(MetricsWebContentsObserver);
 };