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

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

Index: third_party/WebKit/Source/core/mojo/MojoWatcher.cpp
diff --git a/third_party/WebKit/Source/core/mojo/MojoWatcher.cpp b/third_party/WebKit/Source/core/mojo/MojoWatcher.cpp
index 2e0eb8c188d8fd10a68a9045221e05bbde646c59..d25446ad95bd8e7dc64d5c52b06427821ca1131c 100644
--- a/third_party/WebKit/Source/core/mojo/MojoWatcher.cpp
+++ b/third_party/WebKit/Source/core/mojo/MojoWatcher.cpp
@@ -170,6 +170,10 @@ void MojoWatcher::RunReadyCallback(MojoResult result) {
 
   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