ChannelMojo: Let MessagePipeReader wait "peer closed" signal as well.

ipc/mojo/ipc_message_pipe_reader.cc

Index: ipc/mojo/ipc_message_pipe_reader.cc
diff --git a/ipc/mojo/ipc_message_pipe_reader.cc b/ipc/mojo/ipc_message_pipe_reader.cc
index 61b36f6f384531dd68e0d7358f59889e5dca00d0..d40d6e2b228e631d9634167037f871578d71454a 100644
--- a/ipc/mojo/ipc_message_pipe_reader.cc
+++ b/ipc/mojo/ipc_message_pipe_reader.cc
@@ -161,8 +161,9 @@ void MessagePipeReader::ReadMessagesThenWait() {
     // If can fail with |MOJO_RESULT_ALREADY_EXISTS| otherwise.
     // Also, we don't use MOJO_HANDLE_SIGNAL_WRITABLE here, expecting buffer in
     // MessagePipe.
-    MojoResult result =
-        async_waiter_->Wait(pipe_.get().value(), MOJO_HANDLE_SIGNAL_READABLE);
+    MojoResult result = async_waiter_->Wait(
+        pipe_.get().value(),
+        MOJO_HANDLE_SIGNAL_READABLE | MOJO_HANDLE_SIGNAL_PEER_CLOSED);
     // If the result is |MOJO_RESULT_ALREADY_EXISTS|, there could be messages
     // that have been arrived after the last |ReadAvailableMessages()|.
     // We have to consume then and retry in that case.
@@ -180,13 +181,9 @@ void MessagePipeReader::ReadMessagesThenWait() {
 
 void MessagePipeReader::PipeIsReady(MojoResult wait_result) {
   if (wait_result != MOJO_RESULT_OK) {
-    if (wait_result != MOJO_RESULT_ABORTED) {
-      // FAILED_PRECONDITION happens every time the peer is dead so
-      // it isn't worth polluting the log message.
-      LOG_IF(WARNING, wait_result != MOJO_RESULT_FAILED_PRECONDITION)
-          << "Pipe got error from the waiter. Closing: " << wait_result;
-      OnPipeError(wait_result);
-    }
+    CHECK_NE(wait_result, MOJO_RESULT_ABORTED);
+    LOG(ERROR) << "Pipe got error from the waiter. Closing: " << wait_result;
+    OnPipeError(wait_result);
 
     Close();
     return;