Add missing (and remove superfluous) 'explicit' from constructors.

remoting/host/linux/x11_util.h

 // 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.
 
 #ifndef REMOTING_HOST_LINUX_X11_UTIL_H_
 #define REMOTING_HOST_LINUX_X11_UTIL_H_
 
 // Xlib.h defines XErrorEvent as an anonymous struct, so we can't forward-
 // declare it in this header. Since Xlib.h is not generally something you
 // should #include into arbitrary code, please refrain from #including this
@@ skipping 31 matching lines @@
   bool ok_;
 
   DISALLOW_COPY_AND_ASSIGN(ScopedXErrorHandler);
 };
 
 
 // Grab/release the X server within a scope. This can help avoid race
 // conditions that would otherwise lead to X errors.
 class ScopedXGrabServer {
  public:
-  ScopedXGrabServer(Display* display);
+  explicit ScopedXGrabServer(Display* display);
   ~ScopedXGrabServer();
 
  private:
   Display* display_;
 
   DISALLOW_COPY_AND_ASSIGN(ScopedXGrabServer);
 };
 
 }  // namespace remoting
 
 #endif  // REMOTING_HOST_LINUX_X11_UTIL_H_