Revert of Removing the ChildProcessHostMsg_SyncAllocateSharedMemory IPC message.

content/common/child_process_host_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/common/child_process_host_impl.h"
 
 #include <limits>
 
 #include "base/atomic_sequence_num.h"
 #include "base/command_line.h"
@@ skipping 167 matching lines @@
 }
 
 bool ChildProcessHostImpl::Send(IPC::Message* message) {
   if (!channel_) {
     delete message;
     return false;
   }
   return channel_->Send(message);
 }
 
+void ChildProcessHostImpl::AllocateSharedMemory(
+      size_t buffer_size, base::ProcessHandle child_process_handle,
+      base::SharedMemoryHandle* shared_memory_handle) {
+  base::SharedMemory shared_buf;
+  if (!shared_buf.CreateAnonymous(buffer_size)) {
+    *shared_memory_handle = base::SharedMemory::NULLHandle();
+    NOTREACHED() << "Cannot create shared memory buffer";
+    return;
+  }
+  shared_buf.GiveToProcess(child_process_handle, shared_memory_handle);
+}
+
 int ChildProcessHostImpl::GenerateChildProcessUniqueId() {
   // This function must be threadsafe.
   //
   // Historically, this function returned ids started with 1, so in several
   // places in the code a value of 0 (rather than kInvalidUniqueID) was used as
   // an invalid value. So we retain those semantics.
   int id = g_unique_id.GetNext() + 1;
 
   CHECK_NE(0, id);
   CHECK_NE(kInvalidUniqueID, id);
@@ skipping 38 matching lines @@
       handled = true;
       break;
     }
   }
 
   if (!handled) {
     handled = true;
     IPC_BEGIN_MESSAGE_MAP(ChildProcessHostImpl, msg)
       IPC_MESSAGE_HANDLER(ChildProcessHostMsg_ShutdownRequest,
                           OnShutdownRequest)
-      // NB: The SyncAllocateGpuMemoryBuffer and DeletedGpuMemoryBuffer IPCs are
-      // handled here for non-renderer child processes. For renderer processes,
-      // they are handled in RenderMessageFilter.
+      // NB: The SyncAllocateSharedMemory, SyncAllocateGpuMemoryBuffer, and
+      // DeletedGpuMemoryBuffer IPCs are handled here for non-renderer child
+      // processes. For renderer processes, they are handled in
+      // RenderMessageFilter.
+      IPC_MESSAGE_HANDLER(ChildProcessHostMsg_SyncAllocateSharedMemory,
+                          OnAllocateSharedMemory)
       IPC_MESSAGE_HANDLER(ChildProcessHostMsg_SyncAllocateGpuMemoryBuffer,
                           OnAllocateGpuMemoryBuffer)
       IPC_MESSAGE_HANDLER(ChildProcessHostMsg_DeletedGpuMemoryBuffer,
                           OnDeletedGpuMemoryBuffer)
       IPC_MESSAGE_UNHANDLED(handled = false)
     IPC_END_MESSAGE_MAP()
 
     if (!handled)
       handled = delegate_->OnMessageReceived(msg);
   }
@@ skipping 26 matching lines @@
     filters_[i]->OnChannelError();
 
   // This will delete host_, which will also destroy this!
   delegate_->OnChildDisconnected();
 }
 
 void ChildProcessHostImpl::OnBadMessageReceived(const IPC::Message& message) {
   delegate_->OnBadMessageReceived(message);
 }
 
+void ChildProcessHostImpl::OnAllocateSharedMemory(
+    uint32_t buffer_size,
+    base::SharedMemoryHandle* handle) {
+  AllocateSharedMemory(buffer_size, peer_process_.Handle(), handle);
+}
+
 void ChildProcessHostImpl::OnShutdownRequest() {
   if (delegate_->CanShutdown())
     Send(new ChildProcessMsg_Shutdown());
 }
 
 void ChildProcessHostImpl::OnAllocateGpuMemoryBuffer(
     gfx::GpuMemoryBufferId id,
     uint32_t width,
     uint32_t height,
     gfx::BufferFormat format,
@@ skipping 11 matching lines @@
 }
 
 void ChildProcessHostImpl::OnDeletedGpuMemoryBuffer(
     gfx::GpuMemoryBufferId id,
     const gpu::SyncToken& sync_token) {
   // Note: Nothing to do here as ownership of shared memory backed
   // GpuMemoryBuffers is passed with IPC.
 }
 
 }  // namespace content