Fix failure handling in mock4js to throw instead of calling an undefined function.

chrome/third_party/mock4js/mock4js.js

Index: chrome/third_party/mock4js/mock4js.js
diff --git a/chrome/third_party/mock4js/mock4js.js b/chrome/third_party/mock4js/mock4js.js
index 98e5aa000d71c96801e01172e35cf5edf61ae531..5cd02d518dff1c1202967fc12fe81dce4d282c97 100644
--- a/chrome/third_party/mock4js/mock4js.js
+++ b/chrome/third_party/mock4js/mock4js.js
@@ -122,7 +122,7 @@ Mock4JSException.prototype = {
  */ 
 assertThat = function(expected, argumentMatcher) {
 	if(!argumentMatcher.argumentMatches(expected)) {
-		fail("Expected '"+expected+"' to be "+argumentMatcher.describe());
+		throw new Mock4JSException("Expected '"+expected+"' to be "+argumentMatcher.describe());
 	}
 }
 
@@ -622,4 +622,4 @@ Mock.prototype = {
 		}
 		return msg;
 	}
-}
+}