clang/win: Fix a few warnings.

base/process/launch_win.cc

 // Copyright (c) 2012 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/process/launch.h"
 
 #include <fcntl.h>
 #include <io.h>
 #include <shellapi.h>
 #include <windows.h>
@@ skipping 131 matching lines @@
         DPLOG(ERROR);
         return false;
       }
 
       inherit_handles = true;
       flags |= EXTENDED_STARTUPINFO_PRESENT;
     }
   }
 
   if (options.empty_desktop_name)
-    startup_info->lpDesktop = L"";
+    startup_info->lpDesktop = const_cast<wchar_t*>(L"");
   startup_info->dwFlags = STARTF_USESHOWWINDOW;
   startup_info->wShowWindow = options.start_hidden ? SW_HIDE : SW_SHOW;
 
   if (options.stdin_handle || options.stdout_handle || options.stderr_handle) {
     DCHECK(inherit_handles);
     DCHECK(options.stdin_handle);
     DCHECK(options.stdout_handle);
     DCHECK(options.stderr_handle);
     startup_info->dwFlags |= STARTF_USESTDHANDLES;
     startup_info->hStdInput = options.stdin_handle;
@@ skipping 210 matching lines @@
   WaitForSingleObject(proc_info.process_handle(), INFINITE);
 
   return true;
 }
 
 void RaiseProcessToHighPriority() {
   SetPriorityClass(GetCurrentProcess(), HIGH_PRIORITY_CLASS);
 }
 
 }  // namespace base