Add Perceived PageLoad Time (PPLT) metrics for Prerender Experiments,...

chrome/browser/prerender/prerender_manager.h

Index: chrome/browser/prerender/prerender_manager.h
===================================================================
--- chrome/browser/prerender/prerender_manager.h	(revision 72357)
+++ chrome/browser/prerender/prerender_manager.h	(working copy)
@@ -24,6 +24,13 @@
 class PrerenderManager : public base::RefCounted<PrerenderManager>,
                          private base::NonThreadSafe {
  public:
+  enum PrerenderManagerMode {
+    PRERENDER_MODE_DISABLED,
+    PRERENDER_MODE_ENABLED,
+    PRERENDER_MODE_EXPERIMENT_CONTROL_GROUP,
+    PRERENDER_MODE_EXPERIMENT_PRERENDER_GROUP
+  };
+
   // Owned by a Profile object for the lifetime of the profile.
   explicit PrerenderManager(Profile* profile);
 
@@ -47,6 +54,8 @@
   // Returns NULL if the specified URL has not been prerendered.
   PrerenderContents* GetEntry(const GURL& url);
 
+  void RecordPerceivedPageLoadTime(base::TimeDelta pplt);
+
   base::TimeDelta max_prerender_age() const { return max_prerender_age_; }
   void set_max_prerender_age(base::TimeDelta td) { max_prerender_age_ = td; }
   unsigned int max_elements() const { return max_elements_; }
@@ -80,6 +89,8 @@
   // Default maximum age a prerendered element may have, in seconds.
   static const int kDefaultMaxPrerenderAgeSeconds = 20;
 
+  PrerenderManagerMode mode_;
+
   DISALLOW_COPY_AND_ASSIGN(PrerenderManager);
 };