[PPAPI] Fix a bunch of spelling mistakes

ppapi/cpp/dev/file_chooser_dev.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 PPAPI_CPP_DEV_FILE_CHOOSER_DEV_H_
 #define PPAPI_CPP_DEV_FILE_CHOOSER_DEV_H_
 
 #include <vector>
 
 #include "ppapi/c/dev/ppb_file_chooser_dev.h"
@@ skipping 68 matching lines @@
       const CompletionCallbackWithOutput< std::vector<FileRef> >& callback);
 
  protected:
   // Heap-allocated data passed to the CallbackConverter for backwards compat.
   struct ChooseCallbackData0_5 {
     PP_Resource file_chooser;
     PP_ArrayOutput output;
     PP_CompletionCallback original_callback;
   };
 
-  // Provide backwards-compatability for older versions. Converts the old-style
+  // Provide backwards-compatibility for older versions. Converts the old-style
   // 0.5 "iterator" interface to the new-style 0.6 "array output" interface that
   // the caller is expecting.
   //
   // This takes a heap-allocated ChooseCallbackData0_5 struct passed as the
   // user data and deletes it when the call completes.
   static void CallbackConverter(void* user_data, int32_t result);
 };
 
 }  // namespace pp
 
 #endif  // PPAPI_CPP_DEV_FILE_CHOOSER_DEV_H_