Migrate WaitableEvent to enum-based constructor in chrome/

chrome/browser/net/predictor.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/net/predictor.h"
 
 #include <algorithm>
 #include <cmath>
 #include <set>
 #include <sstream>
@@ skipping 776 matching lines @@
   predictor->SaveDnsPrefetchStateForNextStartupAndTrim(
       startup_list, referral_list, completion);
 }
 
 void Predictor::SaveStateForNextStartupAndTrim() {
   if (!predictor_enabled_)
     return;
   if (!CanPreresolveAndPreconnect())
     return;
 
-  base::WaitableEvent completion(true, false);
+  base::WaitableEvent completion(
+      base::WaitableEvent::ResetPolicy::MANUAL,

[Nico, 2016/06/04 01:48:18]

if this must be an enum class i feel it shouldn't have been a nested one. then
these would be half as verbose.

[gab, 2016/06/04 11:45:20]

We thought about that [1] but decided to go this route because every namespace
you remove you have to makeup for with a more specific enum name, i.e.
base::ResetPolicy is too generic and say base::WaitableEventResetPolicy is
merely saving a ::.

[1] https://crbug.com/612843#c11

[Nico, 2016/06/04 16:33:56]

I submit that if every step along the way seems to have made sense but the end
state is base::WaitableEvent::InitialState::NOT_SIGNALED, then one of the steps
along the way wasn't the right step, even if it felt right at the time ;-)

[gab, 2016/06/04 19:03:22]

Hmm, do you have a specific counterproposal? I'm happy to change it if you have
something we all agree is better. 

+      base::WaitableEvent::InitialState::NOT_SIGNALED);
 
   ListPrefUpdate update_startup_list(user_prefs_,
                                      prefs::kDnsPrefetchingStartupList);
   ListPrefUpdate update_referral_list(user_prefs_,
                                       prefs::kDnsPrefetchingHostReferralList);
   if (BrowserThread::CurrentlyOn(BrowserThread::IO)) {
     SaveDnsPrefetchStateForNextStartupAndTrimOnIOThread(
         update_startup_list.Get(),
         update_referral_list.Get(),
         &completion,
@@ skipping 553 matching lines @@
 }
 
 void SimplePredictor::ShutdownOnUIThread() {
   SetShutdown(true);
 }
 
 bool SimplePredictor::CanPrefetchAndPrerender() const { return true; }
 bool SimplePredictor::CanPreresolveAndPreconnect() const { return true; }
 
 }  // namespace chrome_browser_net