user/src/com/google/gwt/user/History.gwt.xml

<!--                                                                        -->
<!-- Copyright 2006 Google Inc. All Rights Reserved.                        -->
<!-- Deferred binding rules for browser selection.                          -->
<!--                                                                        -->
<!-- This module is typically inherited via com.google.gwt.user.User        -->
<!--                                                                        -->
<module>
	<inherits name="com.google.gwt.core.Core"/>
	<inherits name="com.google.gwt.user.UserAgent"/>

	<!-- Fall through to this rule for all other browsers -->
	<replace-with class="com.google.gwt.user.client.impl.HistoryImplStandard">
		<when-type-is class="com.google.gwt.user.client.impl.HistoryImpl"/>
	</replace-with>

	<!-- IE has a completely different history implementation -->
	<replace-with class="com.google.gwt.user.client.impl.HistoryImplIE6">
		<when-type-is class="com.google.gwt.user.client.impl.HistoryImpl"/>
		<when-property-is name="user.agent" value="ie6"/>
	</replace-with>

	<!-- Safari has yet another history implementation -->
	<replace-with class="com.google.gwt.user.client.impl.HistoryImplSafari">
		<when-type-is class="com.google.gwt.user.client.impl.HistoryImpl"/>
		<when-property-is name="user.agent" value="safari"/>
	</replace-with>
</module>