diff --git a/layout/style/test/Makefile.in b/layout/style/test/Makefile.in
index f5f783b748fd..76ba4defd911 100644
--- a/layout/style/test/Makefile.in
+++ b/layout/style/test/Makefile.in
@@ -145,8 +145,6 @@ MOCHITEST_FILES =	test_acid3_test46.html \
 		test_property_database.html \
 		test_priority_preservation.html \
 		test_property_syntax_errors.html \
-		test_redundant_font_download.html \
-		redundant_font_download.sjs \
 		test_rem_unit.html \
 		test_rule_insertion.html \
 		test_rule_serialization.html \
diff --git a/layout/style/test/redundant_font_download.sjs b/layout/style/test/redundant_font_download.sjs
deleted file mode 100644
index 7eb7d8f8df54..000000000000
--- a/layout/style/test/redundant_font_download.sjs
+++ /dev/null
@@ -1,60 +0,0 @@
-const BinaryOutputStream =
-  Components.Constructor("@mozilla.org/binaryoutputstream;1",
-                         "nsIBinaryOutputStream",
-                         "setOutputStream");
-
-// this is simply a hex dump of a red square .PNG image
-const RED_SQUARE =
-  [
-    0x89,  0x50,  0x4E,  0x47,  0x0D,  0x0A,  0x1A,  0x0A,  0x00,  0x00,
-    0x00,  0x0D,  0x49,  0x48,  0x44,  0x52,  0x00,  0x00,  0x00,  0x20,
-    0x00,  0x00,  0x00,  0x20,  0x08,  0x02,  0x00,  0x00,  0x00,  0xFC,
-    0x18,  0xED,  0xA3,  0x00,  0x00,  0x00,  0x01,  0x73,  0x52,  0x47,
-    0x42,  0x00,  0xAE,  0xCE,  0x1C,  0xE9,  0x00,  0x00,  0x00,  0x28,
-    0x49,  0x44,  0x41,  0x54,  0x48,  0xC7,  0xED,  0xCD,  0x41,  0x0D,
-    0x00,  0x00,  0x08,  0x04,  0xA0,  0xD3,  0xFE,  0x9D,  0x35,  0x85,
-    0x0F,  0x37,  0x28,  0x40,  0x4D,  0x6E,  0x75,  0x04,  0x02,  0x81,
-    0x40,  0x20,  0x10,  0x08,  0x04,  0x02,  0xC1,  0x93,  0x60,  0x01,
-    0xA3,  0xC4,  0x01,  0x3F,  0x58,  0x1D,  0xEF,  0x27,  0x00,  0x00,
-    0x00,  0x00,  0x49,  0x45,  0x4E,  0x44,  0xAE,  0x42,  0x60,  0x82
-  ];
-
-function handleRequest(request, response)
-{
-  var query = {};
-  request.queryString.split('&').forEach(function (val) {
-    var [name, value] = val.split('=');
-    query[name] = unescape(value);
-  });
-
-  response.setHeader("Cache-Control", "no-cache");
-
-  response.setStatusLine(request.httpVersion, 200, "OK");
-  response.setHeader("Content-Type", "text/plain", false);
-
-  var log = getState("bug-879963-request-log") || "";
-
-  var stream = new BinaryOutputStream(response.bodyOutputStream);
-
-  if (query["q"] == "init") {
-    log = "init"; // initialize the log, and return a PNG image
-    response.setHeader("Content-Type", "image/png", false);
-    stream.writeByteArray(RED_SQUARE, RED_SQUARE.length);
-  } else if (query["q"] == "image") {
-    log = log + ";" + query["q"];
-    response.setHeader("Content-Type", "image/png", false);
-    stream.writeByteArray(RED_SQUARE, RED_SQUARE.length);
-  } else if (query["q"] == "font") {
-    log = log + ";" + query["q"];
-    // we don't provide a real font; that's ok, OTS will just reject it
-    response.write("Junk");
-  } else if (query["q"] == "report") {
-    // don't include the actual "report" request in the log we return
-    response.write(log);
-  } else {
-    log = log + ";" + query["q"];
-    response.setStatusLine(request.httpVersion, 404, "Not Found");
-  }
-
-  setState("bug-879963-request-log", log);
-}
diff --git a/layout/style/test/test_redundant_font_download.html b/layout/style/test/test_redundant_font_download.html
deleted file mode 100644
index 3cd2df448b0c..000000000000
--- a/layout/style/test/test_redundant_font_download.html
+++ /dev/null
@@ -1,130 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<!-- https://bugzilla.mozilla.org/show_bug.cgi?id=879963 -->
-<head>
-  <meta charset="utf-8">
-  <title>Test for bug 879963</title>
-  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
-</head>
-
-<body>
-  <!-- Two <style> elements with identical @font-face rules.
-       Although multiple @font-face at-rules for the same family are legal,
-       and add faces to the family, we should NOT download the same resource
-       twice just because we have a duplicate face entry. -->
-  <style type="text/css">
-    @font-face {
-      font-family: foo;
-      src: url("redundant_font_download.sjs?q=font");
-    }
-    .test {
-      font-family: foo;
-    }
-  </style>
-
-  <style type="text/css">
-    @font-face {
-      font-family: foo;
-      src: url("redundant_font_download.sjs?q=font");
-    }
-    .test {
-      font-family: foo;
-    }
-  </style>
-
-  <a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=879963">Mozilla Bug 879963</a>
-
-  <div>
-    <!-- the 'init' request returns an image (just so we can see it's working)
-         and initializes the request logging in our sjs server -->
-    <img src="redundant_font_download.sjs?q=init">
-  </div>
-
-  <div id="test">
-    Test
-  </div>
-
-  <div>
-    <img id="image2" src="">
-  </div>
-
-  <script type="application/javascript">
-    // helper to retrieve the server's request log as text
-    function getRequestLog() {
-      var xmlHttp = new XMLHttpRequest();
-      xmlHttp.open("GET", "redundant_font_download.sjs?q=report", false);
-      xmlHttp.send(null);
-      return xmlHttp.responseText;
-    }
-
-    // retrieve just the most recent request the server has seen
-    function getLastRequest() {
-      return getRequestLog().split(";").pop();
-    }
-
-    // poll the server at intervals of 'delay' ms until it has seen a specific request,
-    // or until maxTime ms have passed
-    function waitForRequest(request, delay, maxTime, func) {
-      timeLimit = Date.now() + maxTime;
-      var intervalId = window.setInterval(function() {
-        var req = getLastRequest();
-        if (req == request || Date.now() > timeLimit) {
-          window.clearInterval(intervalId);
-          func();
-        }
-      }.bind(this), delay);
-    }
-
-    // initially disable the second of the <style> elements,
-    // so we only have a single copy of the font-face
-    document.getElementsByTagName("style")[1].disabled = true;
-
-    SimpleTest.waitForExplicitFinish();
-
-    // We perform a series of actions that trigger requests to the .sjs server,
-    // and poll the server's request log at each stage to check that it has
-    // seen the request we expected before we proceed to the next step.
-    function startTest() {
-      is(getRequestLog(), "init", "request log has been initialized");
-
-      // this should trigger a font download
-      document.getElementById("test").className = "test";
-
-      // wait to confirm that the server has received the request
-      waitForRequest("font", 10, 1000, continueTest1);
-    }
-
-    function continueTest1() {
-      is(getRequestLog(), "init;font", "server received font request");
-
-      // trigger a request for the second image, to provide an explicit
-      // delimiter in the log before we enable the second @font-face rule
-      document.getElementById("image2").src = "redundant_font_download.sjs?q=image";
-
-      waitForRequest("image", 10, 1000, continueTest2);
-    }
-
-    function continueTest2() {
-      is(getRequestLog(), "init;font;image", "server received image request");
-
-      // enable the second <style> element: we should NOT see a second font request,
-      // we expect waitForRequest to time out instead
-      document.getElementsByTagName("style")[1].disabled = false;
-
-      waitForRequest("font", 10, 1000, continueTest3);
-    }
-
-    function continueTest3() {
-      is(getRequestLog(), "init;font;image", "should NOT have re-requested the font");
-
-      SimpleTest.finish();
-    }
-
-    startTest();
-
-  </script>
-
-</body>
-
-</html>
