Refactor ownership model for FirstWebContentsProfiler.

chrome/browser/metrics/first_web_contents_profiler.h

Index: chrome/browser/metrics/first_web_contents_profiler.h
diff --git a/chrome/browser/metrics/first_web_contents_profiler.h b/chrome/browser/metrics/first_web_contents_profiler.h
index 0c024231189deae3f1a36d11761dc614ac10ae6f..376e4f6f9cbe40c48a2211897facff95e442caaa 100644
--- a/chrome/browser/metrics/first_web_contents_profiler.h
+++ b/chrome/browser/metrics/first_web_contents_profiler.h
@@ -19,19 +19,10 @@ class WebContents;
 // class.
 class FirstWebContentsProfiler : public content::WebContentsObserver {
  public:
-  class Delegate {
-   public:
-    // Called by the FirstWebContentsProfiler when it is finished collecting
-    // metrics. The delegate should take this opportunity to destroy the
-    // FirstWebContentsProfiler.
-    virtual void ProfilerFinishedCollectingMetrics() = 0;
-  };
-
   // Creates a profiler for the active web contents. If there are multiple
-  // browsers, the first one is chosen. If there are no browsers, returns
-  // nullptr.
-  static scoped_ptr<FirstWebContentsProfiler> CreateProfilerForFirstWebContents(
-      Delegate* delegate);
+  // browsers, the first one is chosen. The resulting FirstWebContentsProfiler
+  // owns itself.
+  static void Start();
 
  private:
   // Reasons for which profiling is deemed complete. Logged in UMA (do not re-
@@ -50,8 +41,8 @@ class FirstWebContentsProfiler : public content::WebContentsObserver {
     ENUM_MAX
   };
 
-  FirstWebContentsProfiler(content::WebContents* web_contents,
-                           Delegate* delegate);
+  explicit FirstWebContentsProfiler(content::WebContents* web_contents);
+  ~FirstWebContentsProfiler() override = default;
 
   // content::WebContentsObserver:
   void DidFirstVisuallyNonEmptyPaint() override;
@@ -64,8 +55,7 @@ class FirstWebContentsProfiler : public content::WebContentsObserver {
   // Whether this instance has finished collecting all of its metrics.
   bool IsFinishedCollectingMetrics();
 
-  // Informs the delegate that this instance has finished collecting all of its
-  // metrics. Logs |finish_reason| to UMA.
+  // Logs |finish_reason| to UMA and deletes this FirstWebContentsProfiler.
   void FinishedCollectingMetrics(FinishReason finish_reason);
 
   // Initialize histograms for unresponsiveness metrics.
@@ -82,9 +72,6 @@ class FirstWebContentsProfiler : public content::WebContentsObserver {
   // Whether an attempt was made to collect the "MainFrameLoad" metric.
   bool collected_load_metric_;
 
-  // |delegate_| owns |this|.
-  Delegate* delegate_;
-
   // Histogram that keeps track of response times for the watched thread.
   base::HistogramBase* responsiveness_histogram_;