Revert of Disable PluginPowerSaverBrowserTest.BackgroundTabPlugins

chrome/browser/plugins/plugin_power_saver_browsertest.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 <stdint.h>
 #include <string>
 #include <utility>
 
 #include "base/command_line.h"
 #include "base/stl_util.h"
@@ skipping 639 matching lines @@
 
 IN_PROC_BROWSER_TEST_F(PluginPowerSaverBrowserTest, ExpandingSmallPlugin) {
   LoadPeripheralPlugin();
   VerifyPluginIsThrottled(GetActiveWebContents(), "plugin");
 
   std::string script = "window.document.getElementById('plugin').height = 400;";
   ASSERT_TRUE(content::ExecuteScript(GetActiveWebContents(), script));
   VerifyPluginMarkedEssential(GetActiveWebContents(), "plugin");
 }
 
-// Flaky on all bots. crbug.com/665706
-IN_PROC_BROWSER_TEST_F(PluginPowerSaverBrowserTest,
-                       DISABLED_BackgroundTabPlugins) {
+IN_PROC_BROWSER_TEST_F(PluginPowerSaverBrowserTest, BackgroundTabPlugins) {
   content::WebContents* background_contents = LoadHTMLInBackgroundTab(
       "<object id='same_origin' data='fake.swf' "
       "    type='application/x-shockwave-flash'></object>"
       "<object id='small_cross_origin' data='http://otherorigin.com/fake1.swf' "
       "    type='application/x-shockwave-flash' width='400' height='80'>"
       "</object>");
 
   EXPECT_FALSE(PluginLoaded(background_contents, "same_origin"));
   EXPECT_FALSE(PluginLoaded(background_contents, "small_cross_origin"));
 
@@ skipping 110 matching lines @@
 IN_PROC_BROWSER_TEST_F(PluginPowerSaverPreferHtmlBrowserTest,
                        ThrottlePluginsOnAllowContentSetting) {
   HostContentSettingsMap* content_settings_map =
       HostContentSettingsMapFactory::GetForProfile(browser()->profile());
 
   content_settings_map->SetDefaultContentSetting(CONTENT_SETTINGS_TYPE_PLUGINS,
                                                  CONTENT_SETTING_ALLOW);
   LoadPeripheralPlugin();
   VerifyPluginIsThrottled(GetActiveWebContents(), "plugin");
 }