Remove obviously unneeded forward declarations in chrome/browser/[abef]*/*.h.

chrome/browser/extensions/extension_devtools_browsertest.cc

Index: chrome/browser/extensions/extension_devtools_browsertest.cc
diff --git a/chrome/browser/extensions/extension_devtools_browsertest.cc b/chrome/browser/extensions/extension_devtools_browsertest.cc
index 85d34ac1b9aae8c1fbd783855acffbee8133ca72..b8f2300522d620a57ec45abab8b6ab6a729c7560 100644
--- a/chrome/browser/extensions/extension_devtools_browsertest.cc
+++ b/chrome/browser/extensions/extension_devtools_browsertest.cc
@@ -1,9 +1,10 @@
-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2010 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/extensions/extension_devtools_browsertest.h"
 
+#include "base/command_line.h"
 #include "chrome/common/chrome_switches.h"
 
 void ExtensionDevToolsBrowserTest::SetUpCommandLine(CommandLine* command_line) {