Revert of [mojo-edk] Simplify multiprocess pipe bootstrap

mojo/shell/runner/host/child_process_host.h

Index: mojo/shell/runner/host/child_process_host.h
diff --git a/mojo/shell/runner/host/child_process_host.h b/mojo/shell/runner/host/child_process_host.h
index 2664d30891d08ed7d6967c0af9899685e5092815..906a1a234322b8292d4be952b964e09184ce2c00 100644
--- a/mojo/shell/runner/host/child_process_host.h
+++ b/mojo/shell/runner/host/child_process_host.h
@@ -71,24 +71,70 @@
   void ExitNow(int32_t exit_code);
 
  protected:
-  void DidStart(const ProcessReadyCallback& callback);
+  void DidStart();
 
  private:
+  // A thread-safe holder for the bootstrap message pipe to this child process.
+  // The pipe is established on an arbitrary thread and may not be connected
+  // until the host's message loop has stopped running.
+  class PipeHolder : public base::RefCountedThreadSafe<PipeHolder> {
+   public:
+    PipeHolder();
+
+    void Reject();
+    void SetPipe(ScopedMessagePipeHandle pipe);
+    ScopedMessagePipeHandle PassPipe();
+
+   private:
+    friend class base::RefCountedThreadSafe<PipeHolder>;
+
+    ~PipeHolder();
+
+    base::Lock lock_;
+    bool reject_pipe_ = false;
+    ScopedMessagePipeHandle pipe_;
+
+    DISALLOW_COPY_AND_ASSIGN(PipeHolder);
+  };
+
   void DoLaunch();
 
   void AppCompleted(int32_t result);
+
+  // Callback for |embedder::CreateChannel()|.
+  void DidCreateChannel(embedder::ChannelInfo* channel_info);
+
+  // Called once |pipe_holder_| is bound to a pipe.
+  void OnMessagePipeCreated();
+
+  // Called when the child process is launched and when the bootstrap
+  // message pipe is created. Once both things have happened (which may happen
+  // in either order), |process_ready_callback_| is invoked.
+  void MaybeNotifyProcessReady();
+
+  // Callback used to receive the child message pipe from the ports EDK.
+  // This may be called on any thread. It will always stash the pipe in
+  // |holder|, and it will then attempt to call |callback| on
+  // |callback_task_runner| (which may or may not still be running tasks.)
+  static void OnParentMessagePipeCreated(
+      scoped_refptr<PipeHolder> holder,
+      scoped_refptr<base::TaskRunner> callback_task_runner,
+      const base::Closure& callback,
+      ScopedMessagePipeHandle pipe);
 
   scoped_refptr<base::TaskRunner> launch_process_runner_;
   bool start_sandboxed_;
   const base::FilePath app_path_;
   base::Process child_process_;
   // Used for the ChildController binding.
-  edk::PlatformChannelPair platform_channel_pair_;
+  embedder::PlatformChannelPair platform_channel_pair_;
   mojom::ChildControllerPtr controller_;
+  embedder::ChannelInfo* channel_info_;
   mojom::ChildController::StartAppCallback on_app_complete_;
-  edk::HandlePassingInformation handle_passing_info_;
+  embedder::HandlePassingInformation handle_passing_info_;
 
-  // Used to back the NodeChannel between the parent and child node.
+  // Used only when --use-new-edk is specified. Used to back the NodeChannel
+  // between the parent and child node.
   scoped_ptr<edk::PlatformChannelPair> node_channel_;
 
   // Since Start() calls a method on another thread, we use an event to block
@@ -97,6 +143,14 @@
 
   // A token the child can use to connect a primordial pipe to the host.
   std::string primordial_pipe_token_;
+
+  // Holds the message pipe to the child process until it is either closed or
+  // bound to the controller interface.
+  scoped_refptr<PipeHolder> pipe_holder_;
+
+  // Invoked exactly once, as soon as the child process's ID is known and
+  // a pipe to the child has been established.
+  ProcessReadyCallback process_ready_callback_;
 
   base::WeakPtrFactory<ChildProcessHost> weak_factory_;