Prerender: Remove PerceivedPLT 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"
@@ skipping 37 matching lines @@
 
   url_ = navigation_handle->GetURL();
   PrerenderManager* prerender_manager = MaybeGetPrerenderManager();
   if (!prerender_manager)
     return;
   if (prerender_manager->IsWebContentsPrerendering(web_contents(), NULL))
     return;
   prerender_manager->RecordNavigation(url_);
 }
 
-void PrerenderTabHelper::DidStopLoading() {
-  // Compute the PPLT metric and report it in a histogram, if needed. If the
-  // page is still prerendering, record the not swapped in page load time
-  // instead.
-  if (!pplt_load_start_.is_null()) {
-    base::TimeTicks now = GetTimeTicksFromPrerenderManager();
-    if (IsPrerendering()) {
-      PrerenderManager* prerender_manager = MaybeGetPrerenderManager();
-      if (prerender_manager) {
-        prerender_manager->RecordPageLoadTimeNotSwappedIn(
-            origin_, now - pplt_load_start_, url_);
-      } else {
-        NOTREACHED();
-      }
-    } else {
-      double fraction_elapsed_at_swapin = -1.0;
-      if (!actual_load_start_.is_null()) {
-        double plt = (now - actual_load_start_).InMillisecondsF();
-        if (plt > 0.0) {
-          fraction_elapsed_at_swapin = 1.0 -
-              (now - pplt_load_start_).InMillisecondsF() / plt;
-        } else {
-          fraction_elapsed_at_swapin = 1.0;
-        }
-        DCHECK_GE(fraction_elapsed_at_swapin, 0.0);
-        DCHECK_LE(fraction_elapsed_at_swapin, 1.0);
-      }
-
-      RecordPerceivedPageLoadTime(
-          now - pplt_load_start_, fraction_elapsed_at_swapin);
-    }
-  }
-
-  // Reset the PPLT metric.
-  pplt_load_start_ = base::TimeTicks();
-  actual_load_start_ = base::TimeTicks();
-}
-
 void PrerenderTabHelper::DidStartNavigation(
     content::NavigationHandle* navigation_handle) {
   if (navigation_handle->IsSameDocument())
     return;
 
   // 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 (!navigation_handle->IsInMainFrame())
     return;
 
-  // Record PPLT state for the beginning of a new navigation.
-  pplt_load_start_ = GetTimeTicksFromPrerenderManager();
-  actual_load_start_ = base::TimeTicks();
-
   MainFrameUrlDidChange(navigation_handle->GetURL());
 }
 
 void PrerenderTabHelper::MainFrameUrlDidChange(const GURL& url) {
   url_ = url;
 }
 
 PrerenderManager* PrerenderTabHelper::MaybeGetPrerenderManager() const {
   return PrerenderManagerFactory::GetForBrowserContext(
       web_contents()->GetBrowserContext());
@@ skipping 13 matching lines @@
 
 bool PrerenderTabHelper::IsPrerendering() {
   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_);

[mattcary, 2017/03/27 14:57:50]

This is the only place navigation_type_ is used AFAICT. It doesn't seem useful
any more; I had to fiddle it a bit putting in the Prefetch histograms, and at
this point it doesn't add much over
PrerenderManager::IsWebContentsPrerendering().

[pasko, 2017/03/27 16:50:40]

oh yes, thanks! I wanted to nuke that too. Forgot. Done.

   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);
-  } 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_);
 }
 
 }  // namespace prerender