Add ExceptionHandler to ModuleSystem, remove heap allocated v8::TryCatch.

chrome/renderer/extensions/event_unittest.cc

Index: chrome/renderer/extensions/event_unittest.cc
diff --git a/chrome/renderer/extensions/event_unittest.cc b/chrome/renderer/extensions/event_unittest.cc
index 62bbf092ffa04f570cf8cb49bdbb757348465af2..edd47c0fc04e26407e159fac7bd4ad08af3b5086 100644
--- a/chrome/renderer/extensions/event_unittest.cc
+++ b/chrome/renderer/extensions/event_unittest.cc
@@ -151,7 +151,7 @@ TEST_F(EventUnittest, NamedEventDispatch) {
       "var e = new event.Event('myevent');"
       "var called = false;"
       "e.addListener(function() { called = true; });"
-      "chromeHidden.Event.dispatchJSON('myevent', []);"
+      "chromeHidden.Event.dispatchEvent('myevent', []);"
       "assert.AssertTrue(called);");
   module_system_->Require("test");
 }