diff --git a/user/src/com/google/gwt/core/CoreWithUserAgent.gwt.xml b/user/src/com/google/gwt/core/CoreWithUserAgent.gwt.xml
index 90efce2..48fa48e 100644
--- a/user/src/com/google/gwt/core/CoreWithUserAgent.gwt.xml
+++ b/user/src/com/google/gwt/core/CoreWithUserAgent.gwt.xml
@@ -31,16 +31,4 @@
     <when-property-is name="compiler.useSourceMaps" value="true"/>
   </replace-with>
 
-  <!-- Utility class to query if source maps are enabled, mainly for testing -->
-  <replace-with class="com.google.gwt.core.client.impl.SourceMapProperty.SourceMapEnabled">
-    <when-type-is class="com.google.gwt.core.client.impl.SourceMapProperty.SourceMapImpl"/>
-    <when-property-is name="compiler.useSourceMaps" value="true"/>
-  </replace-with>
-
-  <!-- If stack trace emulation is on, we can still get accurate stack traces even if sourcemaps are off -->
-  <replace-with class="com.google.gwt.core.client.impl.SourceMapProperty.SourceMapEnabled">
-    <when-type-is class="com.google.gwt.core.client.impl.SourceMapProperty.SourceMapImpl"/>
-    <when-property-is name="compiler.useSourceMaps" value="false"/>
-    <when-property-is name="compiler.stackMode" value="emulated"/>
-  </replace-with>
 </module>
diff --git a/user/src/com/google/gwt/core/client/impl/SourceMapProperty.java b/user/src/com/google/gwt/core/client/impl/SourceMapProperty.java
deleted file mode 100644
index 6e79367..0000000
--- a/user/src/com/google/gwt/core/client/impl/SourceMapProperty.java
+++ /dev/null
@@ -1,87 +0,0 @@
-/*
- * Copyright 2011 Google Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License"); you may not
- * use this file except in compliance with the License. You may obtain a copy of
- * the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * License for the specific language governing permissions and limitations under
- * the License.
- */
-
-package com.google.gwt.core.client.impl;
-
-import com.google.gwt.core.client.GWT;
-
-/**
- * Helper class to query if SourceMaps are enabled and capable of working on the current user
- * agent.
- */
-public class SourceMapProperty {
-
-  static class SourceMapEnabled extends SourceMapImpl {
-
-    public native boolean doesBrowserSupportSourceMaps() /*-{
-      // Chrome only for now, future Firefoxes have promised support
-      return navigator.userAgent.indexOf('Chrome') > -1;
-    }-*/;
-
-    public boolean isSourceMapGenerationOn() {
-      return true;
-    }
-  }
-
-  static class SourceMapEmulated extends SourceMapEnabled {
-
-    public boolean shouldUseSourceMaps() {
-      // pretend emulated stack is a sourcemap
-      return true;
-    }
-  }
-
-  /**
-   * Interface to provide both the compile time and runtime <code>user.agent</code> selection
-   * property value.
-   */
-  static class SourceMapImpl {
-
-    public boolean doesBrowserSupportSourceMaps() {
-      return false;
-    }
-
-    public boolean isSourceMapGenerationOn() {
-      return false;
-    }
-
-    public boolean shouldUseSourceMaps() {
-      return isSourceMapGenerationOn() && doesBrowserSupportSourceMaps();
-    }
-  }
-
-  private static final SourceMapImpl IMPL = GWT.create(SourceMapImpl.class);
-
-  public static boolean doesBrowserSupportSourceMaps() {
-    return IMPL.doesBrowserSupportSourceMaps();
-  }
-
-  /**
-   * True if fully accurate stack traces are possible. True for DevMode, emulated stack traces, and
-   * cases where sourceMaps can work with detailed browser stack trace support.
-   */
-  public static boolean isDetailedDeobfuscatedStackTraceSupported() {
-    return !GWT.isScript() || shouldUseSourceMaps();
-  }
-
-  public static boolean isSourceMapGenerationOn() {
-    return IMPL.isSourceMapGenerationOn();
-  }
-
-  public static boolean shouldUseSourceMaps() {
-    return IMPL.shouldUseSourceMaps();
-  }
-}
diff --git a/user/test/com/google/gwt/user/client/rpc/LoggingRPCTest.java b/user/test/com/google/gwt/user/client/rpc/LoggingRPCTest.java
index 652eaac..40b368f 100644
--- a/user/test/com/google/gwt/user/client/rpc/LoggingRPCTest.java
+++ b/user/test/com/google/gwt/user/client/rpc/LoggingRPCTest.java
@@ -17,7 +17,6 @@
 package com.google.gwt.user.client.rpc;
 
 import com.google.gwt.core.client.GWT;
-import com.google.gwt.core.client.impl.SourceMapProperty;
 import com.google.gwt.junit.client.GWTTestCase;
 
 import java.util.logging.Level;
@@ -32,9 +31,9 @@
    * WARNING! WARNING! If you edit this method or insert any lines of code above this method,you
    * must re-edit the line number constants below;
    */
-  private static final int METHOD_START_LINE = 39;
+  private static final int METHOD_START_LINE = 38;
 
-  private static final int METHOD_EXCEPTION_LINE = 41;
+  private static final int METHOD_EXCEPTION_LINE = 40;
 
   private void throwException(String arg) {
     // prevent inlining by double referencing arg
@@ -163,7 +162,7 @@
               for (StackTraceElement e : thrown.getStackTrace()) {
                 if (e.getFileName().contains("LoggingRPCTest")) {
                   // if DevMode or SourceMaps enabled and Chrome is the browser, check for exact line
-                  if (SourceMapProperty.isDetailedDeobfuscatedStackTraceSupported()) {
+                  if (System.getProperty("user.agent", "safari").equals("safari")) {
                     assertEquals(METHOD_EXCEPTION_LINE, e.getLineNumber());
                   } else {
                     // else fallback to line number of method itself