Fixed all unused-variable Clang warnings on Windows.

chrome/browser/ui/extensions/extension_message_bubble_factory.cc

 // Copyright 2015 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/ui/extensions/extension_message_bubble_factory.h"
 
 #include "base/command_line.h"
 #include "base/lazy_instance.h"
 #include "base/metrics/field_trial.h"
 #include "chrome/browser/extensions/dev_mode_bubble_controller.h"
@@ skipping 15 matching lines @@
 // that are in the different bubble controllers.
 base::LazyInstance<std::set<Profile*> > g_profiles_evaluated =
     LAZY_INSTANCE_INITIALIZER;
 
 // This is used to turn on all bubbles for testing.
 bool g_enabled_for_tests = false;
 
 const char kEnableDevModeWarningExperimentName[] =
     "ExtensionDeveloperModeWarning";
 
+#if !defined(OS_WIN)
 const char kEnableProxyWarningExperimentName[] = "ExtensionProxyWarning";
+#endif
 
 bool IsExperimentEnabled(const char* experiment_name) {
   // Don't allow turning it off via command line.
   base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
   if (command_line->HasSwitch(switches::kForceFieldTrials)) {
     std::string forced_trials =
         command_line->GetSwitchValueASCII(switches::kForceFieldTrials);
     if (forced_trials.find(experiment_name))
       return true;
   }
@@ skipping 96 matching lines @@
       return controller.Pass();
   }
 
   return scoped_ptr<extensions::ExtensionMessageBubbleController>();
 }
 
 // static
 void ExtensionMessageBubbleFactory::set_enabled_for_tests(bool enabled) {
   g_enabled_for_tests = enabled;
 }