Reland r167487: Get full WebPluginInfo for the PDF plug-in before enabling it for print preview.

ui/base/win/window_impl.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 UI_BASE_WIN_WINDOW_IMPL_H_
 #define UI_BASE_WIN_WINDOW_IMPL_H_
 
 #include <atlbase.h>
 #include <atlapp.h>
 #include <atlmisc.h>
@@ skipping 72 matching lines @@
 
  private:
   friend class ClassRegistrar;
 
   // The window procedure used by all Windows.
   static LRESULT CALLBACK WndProc(HWND window,
                                   UINT message,
                                   WPARAM w_param,
                                   LPARAM l_param);
 
-  // Gets the window class name to use when creating the corresponding HWND.
+  // Gets the window class atom to use when creating the corresponding HWND.
   // If necessary, this registers the window class.
-  std::wstring GetWindowClassName();
+  ATOM GetWindowClassAtom();
 
   // All classes registered by WindowImpl start with this name.
   static const wchar_t* const kBaseClassName;
 
   // Window Styles used when creating the window.
   DWORD window_style_;
 
   // Window Extended Styles used when creating the window.
   DWORD window_ex_style_;
 
   // Style of the class to use.
   UINT class_style_;
 
   // Our hwnd.
   HWND hwnd_;
 
   // For debugging.
   // TODO(sky): nuke this when get crash data.
   bool got_create_;
   bool got_valid_hwnd_;
   bool* destroyed_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowImpl);
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_WIN_WINDOW_IMPL_H_