PPAPI/NaCl: Make ImageData for NaCl just use shared memory

ppapi/proxy/ppb_buffer_proxy.cc

 // 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.
 
 #include "ppapi/proxy/ppb_buffer_proxy.h"
 
 #include <vector>
 
 #include "base/logging.h"
 #include "build/build_config.h"
@@ skipping 11 matching lines @@
 
 namespace ppapi {
 namespace proxy {
 
 Buffer::Buffer(const HostResource& resource,
                const base::SharedMemoryHandle& shm_handle,
                uint32_t size)
     : Resource(OBJECT_IS_PROXY, resource),
       shm_(shm_handle, false),
       size_(size),
-      mapped_data_(NULL),
       map_count_(0) {
 }
 
 Buffer::~Buffer() {
   Unmap();
 }
 
 thunk::PPB_Buffer_API* Buffer::AsPPB_Buffer_API() {
   return this;
 }
 
 PP_Bool Buffer::Describe(uint32_t* size_in_bytes) {
   *size_in_bytes = size_;
   return PP_TRUE;
 }
 
 PP_Bool Buffer::IsMapped() {
-  return PP_FromBool(!!mapped_data_);
+  return PP_FromBool(map_count_ > 0);
 }
 
 void* Buffer::Map() {
   if (map_count_++ == 0)
     shm_.Map(size_);
   return shm_.memory();
 }
 
 void Buffer::Unmap() {
   if (--map_count_ == 0)
@@ skipping 80 matching lines @@
 #elif defined(OS_POSIX)
       local_fd;
 #else
   #error Not implemented.
 #endif
   *result_shm_handle = dispatcher->ShareHandleWithRemote(platform_file, false);
 }
 
 }  // namespace proxy
 }  // namespace ppapi