[win] Enable ModuleDatabase behind a flag.

chrome/browser/chrome_browser_field_trials_desktop.cc

 // Copyright 2013 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/chrome_browser_field_trials_desktop.h"
 
 #if defined(OS_WIN)
 #include <windows.h>
 #endif
 
 #include <map>
 #include <string>
 
 #include "base/command_line.h"
 #include "base/debug/activity_tracker.h"
 #include "base/feature_list.h"
 #include "base/files/file_util.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/path_service.h"
 #include "chrome/browser/features.h"
 #include "chrome/browser/prerender/prerender_field_trial.h"
+#include "chrome/common/chrome_features.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/chrome_switches.h"
 #include "components/browser_watcher/features.h"
 #include "components/variations/variations_associated_data.h"
 #include "content/public/common/content_switches.h"
 #include "media/media_features.h"
 
 #if defined(OS_WIN)
 #include "chrome/install_static/install_util.h"
 #include "components/browser_watcher/stability_data_names.h"
@@ skipping 107 matching lines @@
 }
 #endif  // defined(OS_WIN)
 
 }  // namespace
 
 void SetupDesktopFieldTrials() {
   prerender::ConfigurePrerender();
   SetupStunProbeTrial();
 #if defined(OS_WIN)
   SetupStabilityDebugging();
+  base::FeatureList::IsEnabled(features::kModuleDatabase);

[grt (UTC plus 2), 2017/01/06 09:44:57]

apologies if this is a silly question, but why isn't the call in
ChromeBrowserMainPartsWin::PostProfileInit sufficient? i've never needed to do
anything like this here before. have i been doing it wrong?

[chrisha, 2017/01/10 21:01:45]

AFAIK it's not a big deal, it's just that the earlier you "initialize" them the
higher the likelihood of them showing up in the system profile with crash
reports. I was just copying the code below with kDesktopFastShutdown. I'm not
sure if this is good practice or not...

 #endif  // defined(OS_WIN)
   // Activate the experiment as early as possible to increase its visibility
   // (e.g. the likelihood of its presence in the serialized system profile).
   // This also needs to happen before the browser rendez-vous attempt
   // (NotifyOtherProcessOrCreate) in PreMainMessageLoopRun so the corresponding
   // metrics are tagged.
   base::FeatureList::IsEnabled(features::kDesktopFastShutdown);
 }
 
 }  // namespace chrome