Prevent redirector from returning the current module in cases where it fails to look up the first...

chrome_frame/dll_redirector.h

 // Copyright (c) 2011 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 CHROME_FRAME_MODULE_UTILS_H_
-#define CHROME_FRAME_MODULE_UTILS_H_
+#ifndef CHROME_FRAME_DLL_REDIRECTOR_H_
+#define CHROME_FRAME_DLL_REDIRECTOR_H_
 
 #include <ObjBase.h>
 #include <windows.h>
+#include <string>
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/singleton.h"
 #include "base/shared_memory.h"
 
 // Forward
 namespace ATL {
 class CSecurityAttributes;
 }
@@ skipping 22 matching lines @@
   // on the system. If this succeeds, return true. If it fails, it returns
   // false meaning that there is another version already loaded somewhere and
   // the caller should delegate to that version instead.
   bool DllRedirector::RegisterAsFirstCFModule();
 
   // Unregisters the well known window class if we registered it earlier.
   // This is intended to be called from DllMain under PROCESS_DETACH.
   void DllRedirector::UnregisterAsFirstCFModule();
 
   // Helper function to return the DllGetClassObject function pointer from
-  // the given module. On success, the return value is non-null and module
-  // will have had its reference count incremented.
+  // the given module. This function will return NULL unless
+  // RegisterAsFirstCFModule has been called first and returned false
+  // indicating that another module was first in.
+  //
+  // On success, the return value is non-null and the first-in module will have
+  // had its reference count incremented.
   LPFNGETCLASSOBJECT GetDllGetClassObjectPtr();
 
  protected:
   DllRedirector();
   friend struct DefaultSingletonTraits<DllRedirector>;
 
   // Constructor used for tests.
   explicit DllRedirector(const char* shared_memory_name);
 
   // Returns an HMODULE to the version of the module that should be loaded.
@@ skipping 30 matching lines @@
   HMODULE first_module_handle_;
 
   // Used for tests to override the name of the shared memory segment.
   std::string shared_memory_name_;
 
   friend class ModuleUtilsTest;
 
   DISALLOW_COPY_AND_ASSIGN(DllRedirector);
 };
 
-#endif  // CHROME_FRAME_MODULE_UTILS_H_
+#endif  // CHROME_FRAME_DLL_REDIRECTOR_H_