Revert of Removing the ChildProcessHostMsg_SyncAllocateSharedMemory IPC message.

content/child/child_thread_impl.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 "content/child/child_thread_impl.h"
 
 #include <signal.h>
 #include <string>
 #include <utility>
 
@@ skipping 47 matching lines @@
 #include "content/public/common/service_names.h"
 #include "ipc/ipc_channel_mojo.h"
 #include "ipc/ipc_logging.h"
 #include "ipc/ipc_platform_file.h"
 #include "ipc/ipc_sync_channel.h"
 #include "ipc/ipc_sync_message_filter.h"
 #include "mojo/edk/embedder/embedder.h"
 #include "mojo/edk/embedder/named_platform_channel_pair.h"
 #include "mojo/edk/embedder/platform_channel_pair.h"
 #include "mojo/edk/embedder/scoped_ipc_support.h"
-#include "mojo/public/cpp/system/buffer.h"
-#include "mojo/public/cpp/system/platform_handle.h"
 #include "services/service_manager/public/cpp/connector.h"
 #include "services/service_manager/public/cpp/interface_factory.h"
 #include "services/service_manager/public/cpp/interface_provider.h"
 #include "services/service_manager/public/cpp/interface_registry.h"
 #include "services/service_manager/runner/common/client_util.h"
 
 #if defined(OS_POSIX)
 #include "base/posix/global_descriptors.h"
 #include "content/public/common/content_descriptors.h"
 #endif
@@ skipping 644 matching lines @@
     size_t buf_size) {
   DCHECK(message_loop_->task_runner()->BelongsToCurrentThread());
   return AllocateSharedMemory(buf_size, this, nullptr);
 }
 
 // static
 std::unique_ptr<base::SharedMemory> ChildThreadImpl::AllocateSharedMemory(
     size_t buf_size,
     IPC::Sender* sender,
     bool* out_of_memory) {
-  mojo::ScopedSharedBufferHandle mojo_buf =
-      mojo::SharedBufferHandle::Create(buf_size);
-  if (!mojo_buf->is_valid()) {
-    LOG(WARNING) << "Browser failed to allocate shared memory";
+  std::unique_ptr<base::SharedMemory> shared_buf;
+  // Ask the browser to create the shared memory, since this is blocked by the
+  // sandbox on most platforms.
+  base::SharedMemoryHandle shared_mem_handle;
+  if (sender->Send(new ChildProcessHostMsg_SyncAllocateSharedMemory(
+          buf_size, &shared_mem_handle))) {
+    if (base::SharedMemory::IsHandleValid(shared_mem_handle)) {
+      shared_buf.reset(new base::SharedMemory(shared_mem_handle, false));
+    } else {
+      LOG(WARNING) << "Browser failed to allocate shared memory";
+      if (out_of_memory)
+        *out_of_memory = true;
+      return nullptr;
+    }
+  } else {
+    // Send is allowed to fail during shutdown. Return null in this case.
     if (out_of_memory)
-      *out_of_memory = true;
+      *out_of_memory = false;
     return nullptr;
   }
-
-  base::SharedMemoryHandle shared_buf;
-  if (mojo::UnwrapSharedMemoryHandle(std::move(mojo_buf), &shared_buf,
-                                     nullptr, nullptr) != MOJO_RESULT_OK) {
-    LOG(WARNING) << "Browser failed to allocate shared memory";
-    return nullptr;
-  }
-
-  return base::MakeUnique<base::SharedMemory>(shared_buf, false);
+  return shared_buf;
 }
 
 #if defined(OS_LINUX)
 void ChildThreadImpl::SetThreadPriority(base::PlatformThreadId id,
                                         base::ThreadPriority priority) {
   Send(new ChildProcessHostMsg_SetThreadPriority(id, priority));
 }
 #endif
 
 bool ChildThreadImpl::OnMessageReceived(const IPC::Message& msg) {
@@ skipping 154 matching lines @@
   connected_to_browser_ = true;
   child_info_ = local_info;
   browser_info_ = remote_info;
 }
 
 bool ChildThreadImpl::IsInBrowserProcess() const {
   return static_cast<bool>(browser_process_io_runner_);
 }
 
 }  // namespace content