Adds some CHECKs to MessagePumpMojo

The thread watcher appears to be kicking on when we're trying to
remove a handle. Not sure why. This converts some DCHECKs to CHECKs
and fixes handling of the deadline. I suspect none of this will help,
but it's worth a shot.

BUG=399769
TEST=none
R=darin@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=288949

Review URL: https://codereview.chromium.org/454433003

Cr-Commit-Position: refs/heads/master@{#289600}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@289600 0039d316-1c4b-4281-b951-d872f2087c98


CrOS-Libchrome-Original-Commit: 9a4129222945e697c34bd4a3254b338049870a70
diff --git a/base/message_loop/message_loop.cc b/base/message_loop/message_loop.cc
index 69a02a3..ae165ea 100644
--- a/base/message_loop/message_loop.cc
+++ b/base/message_loop/message_loop.cc
@@ -90,6 +90,8 @@
 // time for every task that is added to the MessageLoop incoming queue.
 bool AlwaysNotifyPump(MessageLoop::Type type) {
 #if defined(OS_ANDROID)
+  // The Android UI message loop needs to get notified each time a task is added
+  // to the incoming queue.
   return type == MessageLoop::TYPE_UI || type == MessageLoop::TYPE_JAVA;
 #else
   return false;
@@ -496,8 +498,6 @@
 }
 
 void MessageLoop::ScheduleWork(bool was_empty) {
-  // The Android UI message loop needs to get notified each time
-  // a task is added to the incoming queue.
   if (was_empty || AlwaysNotifyPump(type_))
     pump_->ScheduleWork();
 }