Delete obviously unneeded forward declarations in chrome/browser/*.h.

chrome/browser/app_modal_dialog.h

Index: chrome/browser/app_modal_dialog.h
diff --git a/chrome/browser/app_modal_dialog.h b/chrome/browser/app_modal_dialog.h
index 73e6b83c1e4dd91a24369ec0d30eba7ceaf9b2ee..a3bf31a028a025b0d574c574972d4341944806c1 100644
--- a/chrome/browser/app_modal_dialog.h
+++ b/chrome/browser/app_modal_dialog.h
@@ -1,4 +1,4 @@
-// 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.
 
@@ -27,9 +27,6 @@ typedef GtkWidget* NativeDialog;
 #endif
 
 class TabContents;
-namespace IPC {
-class Message;
-}
 
 // A controller+model base class for modal dialogs.
 class AppModalDialog {