Prerender: Remove MatchComplete

chrome/browser/prerender/prerender_manager.cc

Index: chrome/browser/prerender/prerender_manager.cc
diff --git a/chrome/browser/prerender/prerender_manager.cc b/chrome/browser/prerender/prerender_manager.cc
index f3dedfe3ca6a331ec3c74368df1ee8fef6dfc40a..a65cf4ba52fafca4f2ff597efc3880a95602957b 100644
--- a/chrome/browser/prerender/prerender_manager.cc
+++ b/chrome/browser/prerender/prerender_manager.cc
@@ -86,39 +86,6 @@ const char* const kValidHttpMethods[] = {
 // Length of prerender history, for display in chrome://net-internals
 const int kHistoryLength = 100;
 
-// Indicates whether a Prerender has been cancelled such that we need
-// a dummy replacement for the purpose of recording the correct PPLT for
-// the Match Complete case.
-// Traditionally, "Match" means that a prerendered page was actually visited &
-// the prerender was used.  Our goal is to have "Match" cases line up in the
-// control group & the experiment group, so that we can make meaningful
-// comparisons of improvements.  However, in the control group, since we don't
-// actually perform prerenders, many of the cancellation reasons cannot be
-// detected.  Therefore, in the Prerender group, when we cancel for one of these
-// reasons, we keep track of a dummy Prerender representing what we would
-// have in the control group.  If that dummy prerender in the prerender group
-// would then be swapped in (but isn't actually b/c it's a dummy), we record
-// this as a MatchComplete.  This allows us to compare MatchComplete's
-// across Prerender & Control group which ideally should be lining up.
-// This ensures that there is no bias in terms of the page load times
-// of the pages forming the difference between the two sets.
-
-bool NeedMatchCompleteDummyForFinalStatus(FinalStatus final_status) {
-  return final_status != FINAL_STATUS_USED &&
-      final_status != FINAL_STATUS_TIMED_OUT &&
-      final_status != FINAL_STATUS_MANAGER_SHUTDOWN &&
-      final_status != FINAL_STATUS_PROFILE_DESTROYED &&
-      final_status != FINAL_STATUS_APP_TERMINATING &&
-      final_status != FINAL_STATUS_WINDOW_OPENER &&
-      final_status != FINAL_STATUS_CACHE_OR_HISTORY_CLEARED &&
-      final_status != FINAL_STATUS_CANCELLED &&
-      final_status != FINAL_STATUS_DEVTOOLS_ATTACHED &&
-      final_status != FINAL_STATUS_CROSS_SITE_NAVIGATION_PENDING &&
-      final_status != FINAL_STATUS_PAGE_BEING_CAPTURED &&
-      final_status != FINAL_STATUS_NAVIGATION_UNCOMMITTED &&
-      final_status != FINAL_STATUS_NON_EMPTY_BROWSING_INSTANCE;
-}
-
 }  // namespace
 
 class PrerenderManager::OnCloseWebContentsDeleter
@@ -550,29 +517,8 @@ void PrerenderManager::MoveEntryToPendingDelete(PrerenderContents* entry,
   ScopedVector<PrerenderData>::iterator it =
       FindIteratorForPrerenderContents(entry);
   DCHECK(it != active_prerenders_.end());
-
-  // If this PrerenderContents is being deleted due to a cancellation any time
-  // after the prerender has started then we need to create a dummy replacement
-  // for PPLT accounting purposes for the Match Complete group. This is the case
-  // if the cancellation is for any reason that would not occur in the control
-  // group case.
-  if (entry->prerendering_has_started() &&
-      entry->match_complete_status() ==
-          PrerenderContents::MATCH_COMPLETE_DEFAULT &&
-      NeedMatchCompleteDummyForFinalStatus(final_status) &&
-      ActuallyPrerendering() &&
-      GetMode() == PRERENDER_MODE_EXPERIMENT_MATCH_COMPLETE_GROUP) {
-    // TODO(tburkard): I'd like to DCHECK that we are actually prerendering.
-    // However, what if new conditions are added and
-    // NeedMatchCompleteDummyForFinalStatus is not being updated.  Not sure
-    // what's the best thing to do here.  For now, I will just check whether
-    // we are actually prerendering.
-    (*it)->MakeIntoMatchCompleteReplacement();
-  } else {
-    to_delete_prerenders_.push_back(*it);
-    active_prerenders_.weak_erase(it);
-  }
-
+  to_delete_prerenders_.push_back(*it);
+  active_prerenders_.weak_erase(it);
   // Destroy the old WebContents relatively promptly to reduce resource usage.
   PostCleanupTask();
 }
@@ -632,8 +578,6 @@ const char* PrerenderManager::GetModeString() {
       return "_15MinTTL";
     case PRERENDER_MODE_EXPERIMENT_NO_USE_GROUP:
       return "_NoUse";
-    case PRERENDER_MODE_EXPERIMENT_MATCH_COMPLETE_GROUP:
-      return "_MatchComplete";
     case PRERENDER_MODE_MAX:
     default:
       NOTREACHED() << "Invalid PrerenderManager mode.";
@@ -872,16 +816,6 @@ PrerenderManager::PrerenderData::PrerenderData(PrerenderManager* manager,
 PrerenderManager::PrerenderData::~PrerenderData() {
 }
 
-void PrerenderManager::PrerenderData::MakeIntoMatchCompleteReplacement() {
-  DCHECK(contents_);
-  contents_->set_match_complete_status(
-      PrerenderContents::MATCH_COMPLETE_REPLACED);
-  PrerenderData* to_delete = new PrerenderData(manager_, contents_.release(),
-                                               expiry_time_);
-  contents_.reset(to_delete->contents_->CreateMatchCompleteReplacement());
-  manager_->to_delete_prerenders_.push_back(to_delete);
-}
-
 void PrerenderManager::PrerenderData::OnHandleCreated(PrerenderHandle* handle) {
   DCHECK(contents_);
   ++handle_count_;