[mojo] Add Mojo bindings support for IPC::ParamTraits

mojo/public/cpp/bindings/lib/pickle_buffer.h

 // Copyright 2015 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 MOJO_PUBLIC_CPP_BINDINGS_LIB_PICKLE_BUFFER_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_LIB_PICKLE_BUFFER_H_
 
 #include "base/macros.h"
 #include "base/pickle.h"
 #include "mojo/public/cpp/bindings/lib/buffer.h"
@@ skipping 20 matching lines @@
   }
 
   size_t data_num_bytes() const { return payload_size(); }
 
   // Resizes and zeroes the underlying Pickle's capacity.
   void AllocData(uint32_t num_bytes);
 
   // Resizes the underlying Pickle's capacity without zeroing.
   void AllocUninitializedData(uint32_t num_bytes);
 
+  // Buffer:
+  PickleBuffer* AsPickleBuffer() override;
+
  private:
   // Buffer implementation. Note that this may grow the Pickle's capacity if
   // necessary, but you can avoid this by calling AllocData to preallocate when
   // the final buffer size is known in advance.
   //
   // This guarantees that the returned data is aligned on an 8-byte boundary.
   void* Allocate(size_t num_bytes) override;
 
   // TODO(rockot): Stop wasting 8 bytes per buffer.
   //
@@ skipping 19 matching lines @@
   // claim memory.
   size_t allocation_cursor_ = 0;
 
   DISALLOW_COPY_AND_ASSIGN(PickleBuffer);
 };
 
 }  // namespace internal
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_PICKLE_BUFFER_H_