content: Remove base::WaitableEvent from ChildIOSurfaceManager.

content/child/child_io_surface_manager_mac.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 "content/child/child_io_surface_manager_mac.h"
 
 #include "base/mac/mach_logging.h"
 #include "content/common/mac/io_surface_manager_messages.h"
 
 namespace content {
@@ skipping 75 matching lines @@
       mach_msg(&request.header, MACH_SEND_MSG, sizeof(request), 0,
                MACH_PORT_NULL, MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
   if (kr != KERN_SUCCESS) {
     MACH_LOG(ERROR, kr) << "mach_msg";
   }
 }
 
 IOSurfaceRef ChildIOSurfaceManager::AcquireIOSurface(
     IOSurfaceId io_surface_id) {
   DCHECK(service_port_.is_valid());
-
-  // A valid token is required to acquire an IOSurface. This will wait for a
-  // valid token if one has not yet been set.
-  set_token_event_.Wait();
-#if !defined(NDEBUG)
-  DCHECK(!(set_token_thread_id_ == base::PlatformThread::CurrentRef()));
-#endif
   DCHECK(!token_.IsZero());
 
   mach_port_t reply_port;
   kern_return_t kr = mach_port_allocate(mach_task_self(),
                                         MACH_PORT_RIGHT_RECEIVE, &reply_port);
   if (kr != KERN_SUCCESS) {
     MACH_LOG(ERROR, kr) << "mach_port_allocate";
     return nullptr;
   }
   base::mac::ScopedMachReceiveRight scoped_receive_right(reply_port);
@@ skipping 22 matching lines @@
     return nullptr;
   }
 
   // Deallocate the right after creating an IOSurface reference.
   base::mac::ScopedMachSendRight scoped_io_surface_right(
       data.reply.msg.io_surface_port.name);
 
   return IOSurfaceLookupFromMachPort(scoped_io_surface_right);
 }
 
-ChildIOSurfaceManager::ChildIOSurfaceManager()
-    : set_token_event_(true, false) {}
+ChildIOSurfaceManager::ChildIOSurfaceManager() {}
 
-ChildIOSurfaceManager::~ChildIOSurfaceManager() {
-}
+ChildIOSurfaceManager::~ChildIOSurfaceManager() {}
 
 }  // namespace content