[Prerender] first contentful paint histograms.

chrome/browser/prerender/prerender_histograms.h

Index: chrome/browser/prerender/prerender_histograms.h
diff --git a/chrome/browser/prerender/prerender_histograms.h b/chrome/browser/prerender/prerender_histograms.h
index 7fdc187567504a42fc24806be46898132a984016..0bc936b403e177d6d8dbcde2362e561ff905df86 100644
--- a/chrome/browser/prerender/prerender_histograms.h
+++ b/chrome/browser/prerender/prerender_histograms.h
@@ -52,6 +52,21 @@ class PrerenderHistograms {
                                    NavigationType navigation_type,
                                    const GURL& url);
 
+  // Record perceived first contentful paint time for prerendered pages, the
+  // time from when the user navigates to a page to when it finishes loading.
+  // The actual load may have started prior to navigation due to prerender
+  // hints.
+  void RecordPerceivedFirstContentfulPaintTime(
+      Origin origin,
+      base::TimeDelta perceived_first_contentful_paint,
+      bool was_hidden);
+
+  // Record that a first contentful paint occured, and whether we were able to
+  // successfuly record the perceived FCP.
+  void RecordPerceivedFirstContentfulPaintStatus(Origin origin,
+                                                 bool successful,
+                                                 bool was_hidden);
+
   // Records, in a histogram, the percentage of the page load time that had
   // elapsed by the time it is swapped in.  Values outside of [0, 1.0] are
   // invalid and ignored.
@@ -121,26 +136,39 @@ class PrerenderHistograms {
                                    bool is_main_resource,
                                    int redirect_count) const;
 
-  // Records the time to first contentful paint.
-  // Must not be called for prefetch loads (which are never rendered anyway).
+  // Records the time to first contentful paint in the context of NoState
+  // Prefetch.
+
+  // Must be called for an actual page load, and not be called for prefetch
+  // loads (which are never rendered anyway).
   // |is_no_store| must be true if the main resource has a "no-store" cache
   // control HTTP header.
   // |prefetch_age| must be zero if the page was not prefetched.
-  void RecordFirstContentfulPaint(Origin origin,
-                                  bool is_no_store,
-                                  base::TimeDelta time,
-                                  base::TimeDelta prefetch_age);
+  void RecordNoStateFirstContentfulPaint(Origin origin,
+                                         bool is_no_store,
+                                         base::TimeDelta time,
+                                         base::TimeDelta prefetch_age);
 
   // Returns the name of the histogram used to record the time to first
-  // contentful paint.
+  // contentful paint for NoState Prefetch.
   // Exposed for testing.
-  static std::string GetFirstContentfulPaintHistogramName(
+  static std::string GetNoStateFirstContentfulPaintHistogramName(
       Origin origin,
       bool is_wash,
       bool is_no_store,
       base::TimeDelta prefetch_age);
 
  private:
+  // Returns the name of the histogram used to record the time to first
+  // contentful paint for Prerender.
+  static std::string GetPerceivedFirstContentfulPaintHistogramName(
+      Origin origin,
+      bool is_wash,
+      bool was_hidden);
+
+  // The suffix used for FCP visibility.
+  static std::string FirstContentfulPaintHiddenName(bool was_hidden);
+
   base::TimeTicks GetCurrentTimeTicks() const;
 
   // Returns the time elapsed since the last prerender happened.