Remove DCHECK that crashes.

content/common/frame_messages.h

 // 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.
 
 // IPC messages for interacting with frames.
 // Multiply-included message file, hence no include guard.
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 1451 matching lines @@
                            base::string16 /* in - alert message */,
                            base::string16 /* in - default prompt */,
                            GURL /* in - originating page URL */,
                            content::JavaScriptDialogType /* in - type */,
                            bool /* out - success */,
                            base::string16 /* out - user_input field */)
 
 // Displays a dialog to confirm that the user wants to navigate away from the
 // page. Replies true if yes, and false otherwise. The reply string is ignored,
 // but is included so that we can use OnJavaScriptMessageBoxClosed.
-IPC_SYNC_MESSAGE_ROUTED2_2(FrameHostMsg_RunBeforeUnloadConfirm,
-                           GURL,           /* in - originating frame URL */
-                           bool            /* in - is a reload */,
-                           bool            /* out - success */,
-                           base::string16  /* out - This is ignored.*/)
+IPC_SYNC_MESSAGE_ROUTED1_2(FrameHostMsg_RunBeforeUnloadConfirm,
+                           bool /* in - is a reload */,
+                           bool /* out - success */,
+                           base::string16 /* out - This is ignored.*/)
 
 // Asks the browser to open the color chooser.
 IPC_MESSAGE_ROUTED3(FrameHostMsg_OpenColorChooser,
                     int /* id */,
                     SkColor /* color */,
                     std::vector<content::ColorSuggestion> /* suggestions */)
 
 // Asks the browser to end the color chooser.
 IPC_MESSAGE_ROUTED1(FrameHostMsg_EndColorChooser, int /* id */)
 
@@ skipping 189 matching lines @@
                     int /* nfr_request_id */,
                     float /* distance */)
 
 IPC_MESSAGE_ROUTED0(FrameHostMsg_NavigationHandledByEmbedder)
 #endif
 
 // Adding a new message? Stick to the sort order above: first platform
 // independent FrameMsg, then ifdefs for platform specific FrameMsg, then
 // platform independent FrameHostMsg, then ifdefs for platform specific
 // FrameHostMsg.