Mojo JS bindings: switch all mojo/ layout tests to use the new mode.

third_party/WebKit/Source/core/mojo/MojoWatcher.cpp

 // Copyright 2017 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 "core/mojo/MojoWatcher.h"
 
 #include "bindings/core/v8/MojoWatchCallback.h"
 #include "core/dom/ExecutionContext.h"
 #include "core/dom/TaskRunnerHelper.h"
 #include "core/mojo/MojoHandleSignals.h"
@@ skipping 152 matching lines @@
     }
     return;
   }
 
   // Ignore callbacks if not watching.
   if (!watcher_handle_.is_valid())
     return;
 
   RunWatchCallback(callback_, this, result);
 
+  // The user callback may have canceled watching.
+  if (!watcher_handle_.is_valid())
+    return;
+
   // Rearm the watcher so another notification can fire.
   //
   // TODO(rockot): MojoWatcher should expose some better approximation of the
   // new watcher API, including explicit add and removal of handles from the
   // watcher, as well as explicit arming.
   MojoResult ready_result;
   MojoResult arm_result = Arm(&ready_result);
   if (arm_result == MOJO_RESULT_OK)
     return;
 
   DCHECK_EQ(MOJO_RESULT_FAILED_PRECONDITION, arm_result);
 
   task_runner_->PostTask(BLINK_FROM_HERE,
                          WTF::Bind(&MojoWatcher::RunReadyCallback,
                                    WrapWeakPersistent(this), ready_result));
 }
 
 }  // namespace blink