Add a base::Feature to change progress bar completion policy.

content/common/content_switches_internal.cc

 // Copyright (c) 2014 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 "content/common/content_switches_internal.h"
 
 #include <string>
 
 #include "base/command_line.h"
 #include "base/feature_list.h"
@@ skipping 18 matching lines @@
 bool IsUseZoomForDSFEnabledByDefault() {
 #if defined(OS_CHROMEOS) || defined(OS_LINUX)
   return true;
 #elif defined(OS_WIN)
   return base::FeatureList::IsEnabled(kUseZoomForDsfEnabledByDefault);
 #else
   return false;
 #endif
 }
 
+#if defined(ANDROID)
+const base::Feature kProgressBarCompletionResourcesBeforeDOMContentLoaded{

[Charlie Reis, 2016/10/21 22:07:20]

nit: Is there room for a space before the brace, as above?

[Nate Chapin, 2016/10/21 22:09:22]

Yep, will fix before landing.

+    "progress-bar-completion-resources-before-domContentLoaded",
+    base::FEATURE_DISABLED_BY_DEFAULT};
+#endif
+
 }  // namespace
 
 bool IsPinchToZoomEnabled() {
   const base::CommandLine& command_line =
       *base::CommandLine::ForCurrentProcess();
 
   // Enable pinch everywhere unless it's been explicitly disabled.
   return !command_line.HasSwitch(switches::kDisablePinch);
 }
 
@@ skipping 50 matching lines @@
   if (progress_bar_completion == "loadEvent")
     return ProgressBarCompletion::LOAD_EVENT;
   if (progress_bar_completion == "resourcesBeforeDOMContentLoaded")
     return ProgressBarCompletion::RESOURCES_BEFORE_DCL;
   if (progress_bar_completion == "domContentLoaded")
     return ProgressBarCompletion::DOM_CONTENT_LOADED;
   if (progress_bar_completion ==
       "resourcesBeforeDOMContentLoadedAndSameOriginIframes") {
     return ProgressBarCompletion::RESOURCES_BEFORE_DCL_AND_SAME_ORIGIN_IFRAMES;
   }
+  // The command line, which is set by the user, takes priority. Otherwise,
+  // fall back to the feature flag.
+  if (base::FeatureList::IsEnabled(
+          kProgressBarCompletionResourcesBeforeDOMContentLoaded)) {
+    return ProgressBarCompletion::RESOURCES_BEFORE_DCL;
+  }
 #endif
   return ProgressBarCompletion::LOAD_EVENT;
 }
 
 } // namespace content