Support partitioning of storage contexts based on render_id.

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/atomicops.h"
 #include "base/command_line.h"
@@ skipping 59 matching lines @@
                                .Append(new_basename);
 
   return new_path;
 }
 
 }  // namespace
 #endif  // OS_MACOSX
 
 namespace content {
 
+int ChildProcessHostImpl::kInvalidChildProcessId = -1;
+
 // static
 ChildProcessHost* ChildProcessHost::Create(ChildProcessHostDelegate* delegate) {
   return new ChildProcessHostImpl(delegate);
 }
 
 // static
 FilePath ChildProcessHost::GetChildPath(int flags) {
   FilePath child_path;
 
   child_path = CommandLine::ForCurrentProcess()->GetSwitchValuePath(
@@ skipping 111 matching lines @@
   if (!shared_buf.CreateAndMapAnonymous(buffer_size)) {
     *shared_memory_handle = base::SharedMemory::NULLHandle();
     NOTREACHED() << "Cannot map shared memory buffer";
     return;
   }
   shared_buf.GiveToProcess(child_process_handle, shared_memory_handle);
 }
 
 int ChildProcessHostImpl::GenerateChildProcessUniqueId() {
   // This function must be threadsafe.
+  //
+  // TODO(ajwong): Why not StaticAtomicSequenceNumber?
   static base::subtle::Atomic32 last_unique_child_id = 0;
-  return base::subtle::NoBarrier_AtomicIncrement(&last_unique_child_id, 1);
+  int id = base::subtle::NoBarrier_AtomicIncrement(&last_unique_child_id, 1);
+
+  CHECK_NE(kInvalidChildProcessId, id);
+
+  return id;
 }
 
 bool ChildProcessHostImpl::OnMessageReceived(const IPC::Message& msg) {
 #ifdef IPC_MESSAGE_LOG_ENABLED
   IPC::Logging* logger = IPC::Logging::GetInstance();
   if (msg.type() == IPC_LOGGING_ID) {
     logger->OnReceivedLoggingMessage(msg);
     return true;
   }
 
@@ skipping 56 matching lines @@
     base::SharedMemoryHandle* handle) {
   AllocateSharedMemory(buffer_size, peer_handle_, handle);
 }
 
 void ChildProcessHostImpl::OnShutdownRequest() {
   if (delegate_->CanShutdown())
     Send(new ChildProcessMsg_Shutdown());
 }
 
 }  // namespace content