Revert of [mojo-edk] Simplify multiprocess pipe bootstrap

mojo/shell/runner/child/runner_connection.cc

 // Copyright 2015 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 "mojo/shell/runner/child/runner_connection.h"
 
 #include <stdint.h>
 
 #include <utility>
 
@@ skipping 56 matching lines @@
  private:
   base::WaitableEvent event_;
   base::Closure run_after_;
 
   DISALLOW_COPY_AND_ASSIGN(Blocker);
 };
 
 using GotApplicationRequestCallback =
     base::Callback<void(InterfaceRequest<mojom::ShellClient>)>;
 
+void OnCreateMessagePipe(ScopedMessagePipeHandle* result,
+                         Blocker::Unblocker unblocker,
+                         ScopedMessagePipeHandle pipe) {
+  *result = std::move(pipe);
+  unblocker.Unblock(base::Bind(&base::DoNothing));
+}
+
 void OnGotApplicationRequest(InterfaceRequest<mojom::ShellClient>* out_request,
                              InterfaceRequest<mojom::ShellClient> request) {
   *out_request = std::move(request);
 }
 
 class ChildControllerImpl;
 
 class RunnerConnectionImpl : public RunnerConnection {
  public:
   RunnerConnectionImpl() : controller_thread_("controller_thread") {
@@ skipping 128 matching lines @@
   if (!handle.is_valid()) {
     edk::ScopedPlatformHandle platform_channel =
         edk::PlatformChannelPair::PassClientHandleFromParentProcess(
             *base::CommandLine::ForCurrentProcess());
     if (!platform_channel.is_valid())
       return false;
     edk::SetParentPipeHandle(std::move(platform_channel));
     std::string primordial_pipe_token =
         base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
             switches::kPrimordialPipeToken);
-    handle = edk::CreateChildMessagePipe(primordial_pipe_token);
+    Blocker blocker;
+    edk::CreateChildMessagePipe(
+        primordial_pipe_token,
+        base::Bind(&OnCreateMessagePipe, base::Unretained(&handle),
+                   blocker.GetUnblocker()));
+    blocker.Block();
   }
 
-  DCHECK(handle.is_valid());
-
   Blocker blocker;
   controller_runner_->PostTask(
       FROM_HERE,
       base::Bind(
           &ChildControllerImpl::Create, base::Unretained(this),
           base::Bind(&OnGotApplicationRequest, base::Unretained(request)),
           base::Passed(&handle), blocker.GetUnblocker()));
   blocker.Block();
 
   return true;
@@ skipping 12 matching lines @@
     delete connection;
     return nullptr;
   }
   return connection;
 }
 
 RunnerConnection::RunnerConnection() {}
 
 }  // namespace shell
 }  // namespace mojo