Re-enable Firefox interop test.

chrome/browser/media/webrtc/webrtc_apprtc_browsertest.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 "base/command_line.h"
 #include "base/files/file_enumerator.h"
 #include "base/path_service.h"
 #include "base/process/launch.h"
 #include "base/rand_util.h"
 #include "build/build_config.h"
@@ skipping 254 matching lines @@
   ASSERT_TRUE(WaitForCallToComeUp(right_tab));
 
   ASSERT_TRUE(DetectRemoteVideoPlaying(left_tab));
   ASSERT_TRUE(DetectRemoteVideoPlaying(right_tab));
 
   chrome::CloseWebContents(browser(), left_tab, false);
   chrome::CloseWebContents(browser(), right_tab, false);
 }
 
 #if defined(OS_LINUX)
-// Disabled due to failure. http://crbug.com/648181.
-#define MAYBE_MANUAL_FirefoxApprtcInteropTest DISABLED_MANUAL_FirefoxApprtcInteropTest
+#define MAYBE_MANUAL_FirefoxApprtcInteropTest MANUAL_FirefoxApprtcInteropTest
 #else
 // Not implemented yet on Windows and Mac.
 #define MAYBE_MANUAL_FirefoxApprtcInteropTest DISABLED_MANUAL_FirefoxApprtcInteropTest
 #endif
 
 IN_PROC_BROWSER_TEST_F(WebRtcApprtcBrowserTest,
                        MAYBE_MANUAL_FirefoxApprtcInteropTest) {
   DetectErrorsInJavaScript();
   ASSERT_TRUE(LaunchApprtcInstanceOnLocalhost("9999"));
   ASSERT_TRUE(LaunchColliderOnLocalHost("http://localhost:9999", "8089"));
@@ skipping 12 matching lines @@
       InfoBarService::FromWebContents(chrome_tab), InfoBarResponder::ACCEPT);
   ui_test_utils::NavigateToURL(browser(), room_url);
 
   ASSERT_TRUE(LaunchFirefoxWithUrl(room_url));
 
   ASSERT_TRUE(WaitForCallToComeUp(chrome_tab));
 
   // Ensure Firefox manages to send video our way.
   ASSERT_TRUE(DetectRemoteVideoPlaying(chrome_tab));
 }