Revert of Mojo: Armed Watchers

mojo/public/cpp/bindings/lib/connector.cc

Index: mojo/public/cpp/bindings/lib/connector.cc
diff --git a/mojo/public/cpp/bindings/lib/connector.cc b/mojo/public/cpp/bindings/lib/connector.cc
index ff9867a27c5004b6c216698c3027964ef205321f..4426defa934cd0362ecc2eec712730a55dbf04a9 100644
--- a/mojo/public/cpp/bindings/lib/connector.cc
+++ b/mojo/public/cpp/bindings/lib/connector.cc
@@ -188,12 +188,6 @@
   }
 }
 
-void Connector::EnableNestedDispatch(bool enabled) {
-  nested_dispatch_enabled_ = enabled;
-  handle_watcher_.reset();
-  WaitToReadMore();
-}
-
 void Connector::OnWatcherHandleReady(MojoResult result) {
   OnHandleReadyInternal(result);
 }
@@ -217,7 +211,6 @@
     HandleError(result != MOJO_RESULT_FAILED_PRECONDITION, false);
     return;
   }
-
   ReadAllAvailableMessages();
   // At this point, this object might have been deleted. Return.
 }
@@ -226,11 +219,10 @@
   CHECK(!paused_);
   DCHECK(!handle_watcher_);
 
-  handle_watcher_.reset(new SimpleWatcher(
-      FROM_HERE, SimpleWatcher::ArmingPolicy::MANUAL, task_runner_));
+  handle_watcher_.reset(new Watcher(FROM_HERE, task_runner_));
   if (heap_profiler_tag_)
     handle_watcher_->set_heap_profiler_tag(heap_profiler_tag_);
-  MojoResult rv = handle_watcher_->Watch(
+  MojoResult rv = handle_watcher_->Start(
       message_pipe_.get(), MOJO_HANDLE_SIGNAL_READABLE,
       base::Bind(&Connector::OnWatcherHandleReady, base::Unretained(this)));
 
@@ -240,8 +232,6 @@
     task_runner_->PostTask(
         FROM_HERE,
         base::Bind(&Connector::OnWatcherHandleReady, weak_self_, rv));
-  } else {
-    handle_watcher_->ArmOrNotify();
   }
 
   if (allow_woken_up_by_others_) {
@@ -263,13 +253,6 @@
   const MojoResult rv = ReadMessage(message_pipe_.get(), &message);
   *read_result = rv;
 
-  if (nested_dispatch_enabled_) {
-    // When supporting nested dispatch, we have to rearm the Watcher immediately
-    // after reading each message (i.e. before dispatch) to ensure that the next
-    // inbound message can trigger OnHandleReady on the nested loop.
-    handle_watcher_->ArmOrNotify();
-  }
-
   if (rv == MOJO_RESULT_OK) {
     receiver_result =
         incoming_receiver_ && incoming_receiver_->Accept(&message);
@@ -295,36 +278,19 @@
 
 void Connector::ReadAllAvailableMessages() {
   while (!error_) {
-    base::WeakPtr<Connector> weak_self = weak_self_;
     MojoResult rv;
 
-    // May delete |this.|
-    if (!ReadSingleMessage(&rv))
+    if (!ReadSingleMessage(&rv)) {
+      // Return immediately without touching any members. |this| may have been
+      // destroyed.
       return;
-
-    if (!weak_self || paused_)
+    }
+
+    if (paused_)
       return;
 
-    DCHECK(rv == MOJO_RESULT_OK || rv == MOJO_RESULT_SHOULD_WAIT);
-
-    if (rv == MOJO_RESULT_SHOULD_WAIT) {
-      // Attempt to re-arm the Watcher.
-      MojoResult ready_result;
-      MojoResult arm_result = handle_watcher_->Arm(&ready_result);
-      if (arm_result == MOJO_RESULT_OK)
-        return;
-
-      // The watcher is already ready to notify again.
-      DCHECK_EQ(MOJO_RESULT_FAILED_PRECONDITION, arm_result);
-
-      if (ready_result == MOJO_RESULT_FAILED_PRECONDITION) {
-        HandleError(false, false);
-        return;
-      }
-
-      // There's more to read now, so we'll just keep looping.
-      DCHECK_EQ(MOJO_RESULT_OK, ready_result);
-    }
+    if (rv == MOJO_RESULT_SHOULD_WAIT)
+      break;
   }
 }