customtabs: Send time to first contentful paint to the caller.

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_METRICS_WEB_CONTENTS_OBSERVER_H_
 #define COMPONENTS_PAGE_LOAD_METRICS_BROWSER_METRICS_WEB_CONTENTS_OBSERVER_H_
 
 #include <map>
 #include <memory>
 #include <vector>
@@ skipping 90 matching lines @@
   ERR_LAST_ENTRY,
 };
 
 // This class serves as a functional interface to various chrome// features.
 // Impl version is defined in chrome/browser/page_load_metrics.
 class PageLoadMetricsEmbedderInterface {
  public:
   virtual ~PageLoadMetricsEmbedderInterface() {}
   virtual bool IsPrerendering(content::WebContents* web_contents) = 0;
   virtual bool IsNewTabPageUrl(const GURL& url) = 0;
-  virtual void RegisterObservers(PageLoadTracker* metrics) = 0;
+  virtual void RegisterObservers(PageLoadTracker* metrics,
+                                 content::WebContents* web_contents) = 0;

[Bryan McQuade, 2016/07/21 23:56:13]

the PageLoadMetricsEmbedder implementation now has a web_contents_ member, so
you shouldn't need to pass it as a param here.

[Benoit L, 2016/07/22 15:41:31]

Ah, thanks!
Done.

 };
 
 // This class tracks a given page load, starting from navigation start /
 // provisional load, until a new navigation commits or the navigation fails.
 // MetricsWebContentsObserver manages a set of provisional PageLoadTrackers, as
 // well as a committed PageLoadTracker.
 class PageLoadTracker {
  public:
   // Caller must guarantee that the embedder_interface pointer outlives this
   // class. The PageLoadTracker must not hold on to
@@ skipping 220 matching lines @@
 
   // Has the MWCO observed at least one navigation?
   bool has_navigated_;
 
   DISALLOW_COPY_AND_ASSIGN(MetricsWebContentsObserver);
 };
 
 }  // namespace page_load_metrics
 
 #endif  // COMPONENTS_PAGE_LOAD_METRICS_BROWSER_METRICS_WEB_CONTENTS_OBSERVER_H_