Remove utility process batch mode support and its IPCs

The utility_process_host_impl batch mode feature has no users
anymore, nor is it a useful feature in the age of mojo. Ditch
the feature:

  - remove batch mode IPC and the message file.
  - remove StartBatchMode / EndBatchMode code.
  - change IPC unit tests to use AutomationMsgStart
    IPC start name (instead of UtilityMsgStart).
  - remove UtilityMsgStart IPC message start name.
  - utility_process_host_impl.*, document members
    and remove old / unused #include files.
  - utility_thread{,impl}.h, ditto.

No change in behavior, no new tests.

Bug: 738648
Change-Id: Ifcb65939ba7bf0a52451d2b8cb3a8a254399fcd2
Reviewed-on: https://chromium-review.googlesource.com/558526
Commit-Queue: Noel Gordon <noel@chromium.org>
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Reviewed-by: Ken Rockot <rockot@chromium.org>
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Reviewed-by: Sam McNally <sammc@chromium.org>
Cr-Commit-Position: refs/heads/master@{#484557}

CrOS-Libchrome-Original-Commit: 93d53afdce310ac3f259c01c8d33908b912b427a
diff --git a/ipc/ipc_channel_proxy_unittest.cc b/ipc/ipc_channel_proxy_unittest.cc
index f059099..01b8955 100644
--- a/ipc/ipc_channel_proxy_unittest.cc
+++ b/ipc/ipc_channel_proxy_unittest.cc
@@ -90,7 +90,7 @@
     IPC_BEGIN_MESSAGE_MAP(ChannelReflectorListener, message)
       IPC_MESSAGE_HANDLER(TestMsg_Bounce, OnTestBounce)
       IPC_MESSAGE_HANDLER(TestMsg_SendBadMessage, OnSendBadMessage)
-      IPC_MESSAGE_HANDLER(UtilityMsg_Bounce, OnUtilityBounce)
+      IPC_MESSAGE_HANDLER(AutomationMsg_Bounce, OnAutomationBounce)
       IPC_MESSAGE_HANDLER(WorkerMsg_Bounce, OnBounce)
       IPC_MESSAGE_HANDLER(WorkerMsg_Quit, OnQuit)
     IPC_END_MESSAGE_MAP()
@@ -105,9 +105,7 @@
     channel_->Send(new TestMsg_BadMessage(BadType()));
   }
 
-  void OnUtilityBounce() {
-    channel_->Send(new UtilityMsg_Bounce());
-  }
+  void OnAutomationBounce() { channel_->Send(new AutomationMsg_Bounce()); }
 
   void OnBounce() {
     channel_->Send(new WorkerMsg_Bounce());
@@ -282,17 +280,17 @@
 
 TEST_F(IPCChannelProxyTest, MessageClassFilters) {
   // Construct a filter per message class.
-  std::vector<scoped_refptr<MessageCountFilter> > class_filters;
-  class_filters.push_back(make_scoped_refptr(
-      new MessageCountFilter(TestMsgStart)));
-  class_filters.push_back(make_scoped_refptr(
-      new MessageCountFilter(UtilityMsgStart)));
+  std::vector<scoped_refptr<MessageCountFilter>> class_filters;
+  class_filters.push_back(
+      make_scoped_refptr(new MessageCountFilter(TestMsgStart)));
+  class_filters.push_back(
+      make_scoped_refptr(new MessageCountFilter(AutomationMsgStart)));
   for (size_t i = 0; i < class_filters.size(); ++i)
     channel_proxy()->AddFilter(class_filters[i].get());
 
   // Send a message for each class; each filter should receive just one message.
-  sender()->Send(new TestMsg_Bounce());
-  sender()->Send(new UtilityMsg_Bounce());
+  sender()->Send(new TestMsg_Bounce);
+  sender()->Send(new AutomationMsg_Bounce);
 
   // Send some messages not assigned to a specific or valid message class.
   sender()->Send(new WorkerMsg_Bounce);
@@ -320,7 +318,7 @@
   sender()->Send(new TestMsg_Bounce);
 
   // A message of a different class should be seen only by the global filter.
-  sender()->Send(new UtilityMsg_Bounce);
+  sender()->Send(new AutomationMsg_Bounce);
 
   // Flush all messages.
   SendQuitMessageAndWaitForIdle();
@@ -347,7 +345,7 @@
 
   // Send some messages; they should not be seen by either filter.
   sender()->Send(new TestMsg_Bounce);
-  sender()->Send(new UtilityMsg_Bounce);
+  sender()->Send(new AutomationMsg_Bounce);
 
   // Ensure that the filters were removed and did not receive any messages.
   SendQuitMessageAndWaitForIdle();