[Prerender] first contentful paint histograms.

chrome/browser/prerender/prerender_tab_helper.cc

 // Copyright (c) 2012 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.
 
 #include "chrome/browser/prerender/prerender_tab_helper.h"
 
 #include "base/bind.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/time/time.h"
 #include "chrome/browser/prerender/prerender_histograms.h"
 #include "chrome/browser/prerender/prerender_manager.h"
 #include "chrome/browser/prerender/prerender_manager_factory.h"
 #include "chrome/browser/profiles/profile.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/resource_request_details.h"
 #include "content/public/browser/web_contents.h"
 
 using content::WebContents;
 
 DEFINE_WEB_CONTENTS_USER_DATA_KEY(prerender::PrerenderTabHelper);
 
 namespace prerender {
 
 PrerenderTabHelper::PrerenderTabHelper(content::WebContents* web_contents)
     : content::WebContentsObserver(web_contents),
       origin_(ORIGIN_NONE),
-      weak_factory_(this) {
-  // Determine if this is a prerender.
-  PrerenderManager* prerender_manager = MaybeGetPrerenderManager();
-  if (prerender_manager &&
-      prerender_manager->IsWebContentsPrerendering(web_contents, &origin_)) {
-    navigation_type_ = NAVIGATION_TYPE_PRERENDERED;
-  } else {
-    navigation_type_ = NAVIGATION_TYPE_NORMAL;
-  }
-}
+      weak_factory_(this) {}
 
 PrerenderTabHelper::~PrerenderTabHelper() {
 }
 
 void PrerenderTabHelper::DidGetRedirectForResourceRequest(
     const content::ResourceRedirectDetails& details) {
   if (details.resource_type != content::RESOURCE_TYPE_MAIN_FRAME)
     return;
 
   MainFrameUrlDidChange(details.new_url);
@@ skipping 49 matching lines @@
 
   // Reset the PPLT metric.
   pplt_load_start_ = base::TimeTicks();
   actual_load_start_ = base::TimeTicks();
 }
 
 void PrerenderTabHelper::DidStartProvisionalLoadForFrame(
     content::RenderFrameHost* render_frame_host,
     const GURL& validated_url,
     bool is_error_page) {
+  // Determine the navigation type.
+  PrerenderManager* prerender_manager = MaybeGetPrerenderManager();
+  if (prerender_manager &&
+      prerender_manager->IsWebContentsPrerendering(web_contents(), &origin_)) {
+    navigation_type_ = NAVIGATION_TYPE_PRERENDERED;
+  } else {
+    navigation_type_ = NAVIGATION_TYPE_NORMAL;
+  }
+
   if (render_frame_host->GetParent())
     return;
 
   // Record PPLT state for the beginning of a new navigation.
   pplt_load_start_ = GetTimeTicksFromPrerenderManager();
   actual_load_start_ = base::TimeTicks();
 
   MainFrameUrlDidChange(validated_url);
 }
 
@@ skipping 22 matching lines @@
   PrerenderManager* prerender_manager = MaybeGetPrerenderManager();
   if (!prerender_manager)
     return false;
   return prerender_manager->IsWebContentsPrerendering(web_contents(), NULL);
 }
 
 void PrerenderTabHelper::PrerenderSwappedIn() {
   // Ensure we are not prerendering any more.
   DCHECK_EQ(NAVIGATION_TYPE_PRERENDERED, navigation_type_);
   DCHECK(!IsPrerendering());
+  swap_ticks_ = GetTimeTicksFromPrerenderManager();
   if (pplt_load_start_.is_null()) {
     // If we have already finished loading, report a 0 PPLT.
     RecordPerceivedPageLoadTime(base::TimeDelta(), 1.0);
-    DCHECK_EQ(NAVIGATION_TYPE_NORMAL, navigation_type_);
   } else {
     // If we have not finished loading yet, record the actual load start, and
     // rebase the start time to now.
     actual_load_start_ = pplt_load_start_;
     pplt_load_start_ = GetTimeTicksFromPrerenderManager();
   }
 }
 
 void PrerenderTabHelper::RecordPerceivedPageLoadTime(
     base::TimeDelta perceived_page_load_time,
     double fraction_plt_elapsed_at_swap_in) {
   DCHECK(!IsPrerendering());
   PrerenderManager* prerender_manager = MaybeGetPrerenderManager();
   if (!prerender_manager)
     return;
 
   prerender_manager->RecordPerceivedPageLoadTime(
       origin_, navigation_type_, perceived_page_load_time,
       fraction_plt_elapsed_at_swap_in, url_);
-
-  // Reset state for the next navigation.
-  navigation_type_ = NAVIGATION_TYPE_NORMAL;
-  origin_ = ORIGIN_NONE;
 }
 
 }  // namespace prerender