Use HTTP response headers for PNaCl caching instead of bitcode hash.

ppapi/cpp/completion_callback.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_COMPLETION_CALLBACK_H_
 #define PPAPI_CPP_COMPLETION_CALLBACK_H_
 
 #include "ppapi/c/pp_completion_callback.h"
 #include "ppapi/c/pp_errors.h"
 #include "ppapi/cpp/extensions/ext_output_traits.h"
@@ skipping 67 matching lines @@
   /// @param[in] result The result of the operation to be passed to the
   /// callback function. Non-positive values correspond to the error codes
   /// from <code>pp_errors.h</code> (excluding
   /// <code>PP_OK_COMPLETIONPENDING</code>). Positive values indicate
   /// additional information such as bytes read.
   void Run(int32_t result) {
     PP_DCHECK(cc_.func);
     PP_RunCompletionCallback(&cc_, result);
   }
 
+  /// RunAndClear() is used to run the <code>CompletionCallback</code> and
+  /// clear out the callback so that it cannot be run a second time.
+  ///
+  /// @param[in] result The result of the operation to be passed to the
+  /// callback function. Non-positive values correspond to the error codes
+  /// from <code>pp_errors.h</code> (excluding
+  /// <code>PP_OK_COMPLETIONPENDING</code>). Positive values indicate
+  /// additional information such as bytes read.
+  void RunAndClear(int32_t result) {
+    PP_DCHECK(cc_.func);
+    PP_RunAndClearCompletionCallback(&cc_, result);
+  }
+
   /// IsOptional() is used to determine the setting of the
   /// <code>PP_COMPLETIONCALLBACK_FLAG_OPTIONAL</code> flag. This flag allows
   /// any method taking such callback to complete synchronously
   /// and not call the callback if the operation would not block. This is useful
   /// when performance is an issue, and the operation bandwidth should not be
   /// limited to the processing speed of the message loop.
   ///
   /// On synchronous method completion, the completion result will be returned
   /// by the method itself. Otherwise, the method will return
   /// PP_OK_COMPLETIONPENDING, and the callback will be invoked asynchronously
@@ skipping 263 matching lines @@
 /// @return A <code>CompletionCallback</code> corresponding to a NULL callback.
 inline CompletionCallback BlockUntilComplete() {
   // Note: Explicitly inlined to avoid link errors when included into
   // ppapi_proxy and ppapi_cpp_objects.
   return CompletionCallback();
 }
 
 }  // namespace pp
 
 #endif  // PPAPI_CPP_COMPLETION_CALLBACK_H_