Fix prerender histograms for multiple prerender case.

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/metrics/histogram.h"
 #include "base/string_number_conversions.h"
 #include "base/time.h"
 #include "chrome/browser/prerender/prerender_histograms.h"
@@ skipping 72 matching lines @@
     if (bitmap_web_contents_ != web_contents)
       return;
 
     if (bitmap_type == BITMAP_SWAP_IN)
       bitmap_.swap(bitmap);
 
     if (bitmap_type == BITMAP_ON_LOAD) {
       PrerenderManager* prerender_manager =
           tab_helper_->MaybeGetPrerenderManager();
       if (prerender_manager) {
-        prerender_manager->histograms()->RecordFractionPixelsFinalAtSwapin(
-            CompareBitmaps(bitmap_.get(), bitmap.get()));
+        prerender_manager->RecordFractionPixelsFinalAtSwapin(
+            web_contents, CompareBitmaps(bitmap_.get(), bitmap.get()));
       }
       bitmap_.reset();
       bitmap_web_contents_ = NULL;
     }
   }
 
   // Helper comparing two bitmaps of identical size.
   // Returns a value < 0.0 if there is an error, and otherwise, a double in
   // [0, 1] indicating the fraction of pixels that are the same.
   double CompareBitmaps(SkBitmap* bitmap1, SkBitmap* bitmap2) {
@@ skipping 116 matching lines @@
   PrerenderManager* prerender_manager = MaybeGetPrerenderManager();
   if (!prerender_manager)
     return false;
   return prerender_manager->IsWebContentsPrerendering(web_contents());
 }
 
 bool PrerenderTabHelper::IsPrerendered() {
   PrerenderManager* prerender_manager = MaybeGetPrerenderManager();
   if (!prerender_manager)
     return false;
-  return prerender_manager->IsWebContentsPrerendered(web_contents());
+  return prerender_manager->IsWebContentsPrerendered(web_contents(), NULL);
 }
 
 void PrerenderTabHelper::PrerenderSwappedIn() {
   // Ensure we are not prerendering any more.
   DCHECK(!IsPrerendering());
   if (pplt_load_start_.is_null()) {
     // If we have already finished loading, report a 0 PPLT.
     PrerenderManager::RecordPerceivedPageLoadTime(base::TimeDelta(), 1.0,
                                                   web_contents(), url_);
     PrerenderManager* prerender_manager = MaybeGetPrerenderManager();
     if (prerender_manager)
-      prerender_manager->histograms()->RecordFractionPixelsFinalAtSwapin(1.0);
+      prerender_manager->RecordFractionPixelsFinalAtSwapin(web_contents(), 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_ = base::TimeTicks::Now();
     if (pixel_stats_.get())
       pixel_stats_->GetBitmap(PixelStats::BITMAP_SWAP_IN, web_contents());
   }
 }
 
 }  // namespace prerender