diff --git a/layout/style/test/Makefile.in b/layout/style/test/Makefile.in
index 3ac74cdf610..a7e26ab0d93 100644
--- a/layout/style/test/Makefile.in
+++ b/layout/style/test/Makefile.in
@@ -72,12 +72,17 @@ _TEST_FILES = 	test_bug302186.html \
 		test_bug372770.html \
 		test_bug373293.html \
 		test_inherit_storage.html \
+		test_inherit_computation.html \
 		test_initial_storage.html \
+		test_initial_computation.html \
 		test_property_database.html \
 		test_property_syntax_errors.html \
 		test_value_storage.html \
+		test_value_computation.html \
 		css_properties.js \
 		property_database.js \
+		unstyled.xml \
+		unstyled.css \
 		$(NULL)
 
 
diff --git a/layout/style/test/property_database.js b/layout/style/test/property_database.js
index 76d985462b2..5e29b1bb2eb 100644
--- a/layout/style/test/property_database.js
+++ b/layout/style/test/property_database.js
@@ -240,7 +240,7 @@ var gCSSProperties = {
 		inherited: false,
 		type: CSS_TYPE_LONGHAND,
 		initial_values: [ "auto" ],
-		other_values: [ "50%", "15px" ],
+		other_values: [ "15px", "50%" ],
 		invalid_values: [ "20" ]
 	},
 	"-moz-float-edge": {
@@ -261,7 +261,7 @@ var gCSSProperties = {
 	},
 	"-moz-image-region": {
 		domProp: "MozImageRegion",
-		inherited: false,
+		inherited: true,
 		type: CSS_TYPE_LONGHAND,
 		initial_values: [ "auto" ],
 		other_values: [ "rect(3px 20px 15px 4px)", "rect(17px, 21px, 33px, 2px)" ],
@@ -480,7 +480,7 @@ var gCSSProperties = {
 		domProp: "borderBottomWidth",
 		inherited: false,
 		type: CSS_TYPE_LONGHAND,
-		/* XXX a value differing from initial requires border-style to be set */
+		prerequisites: { "border-bottom-style": "solid" },
 		initial_values: [ "medium", "3px" ],
 		other_values: [ "thin", "thick", "1px", "2em" ],
 		invalid_values: [ "5%" ]
@@ -532,7 +532,7 @@ var gCSSProperties = {
 		domProp: "borderLeftWidth",
 		inherited: false,
 		type: CSS_TYPE_LONGHAND,
-		/* XXX a value differing from initial requires border-style to be set */
+		prerequisites: { "border-left-style": "solid" },
 		initial_values: [ "medium", "3px" ],
 		other_values: [ "thin", "thick", "1px", "2em" ],
 		invalid_values: [ "5%" ]
@@ -567,7 +567,7 @@ var gCSSProperties = {
 		domProp: "borderRightWidth",
 		inherited: false,
 		type: CSS_TYPE_LONGHAND,
-		/* XXX a value differing from initial requires border-style to be set */
+		prerequisites: { "border-right-style": "solid" },
 		initial_values: [ "medium", "3px" ],
 		other_values: [ "thin", "thick", "1px", "2em" ],
 		invalid_values: [ "5%" ]
@@ -620,7 +620,7 @@ var gCSSProperties = {
 		domProp: "borderTopWidth",
 		inherited: false,
 		type: CSS_TYPE_LONGHAND,
-		/* XXX a value differing from initial requires border-style to be set */
+		prerequisites: { "border-top-style": "solid" },
 		initial_values: [ "medium", "3px" ],
 		other_values: [ "thin", "thick", "1px", "2em" ],
 		invalid_values: [ "5%" ]
@@ -630,7 +630,7 @@ var gCSSProperties = {
 		inherited: false,
 		type: CSS_TYPE_TRUE_SHORTHAND,
 		subproperties: [ "border-top-width", "border-right-width", "border-bottom-width", "border-left-width" ],
-		/* XXX a value differing from initial requires border-style to be set */
+		prerequisites: { "border-style": "solid" },
 		initial_values: [ "medium", "3px", "medium medium", "3px medium medium", "medium 3px medium medium" ],
 		other_values: [ "thin", "thick", "1px", "2em", "2px 0 0px 1em" ],
 		invalid_values: [ "5%" ]
@@ -666,14 +666,15 @@ var gCSSProperties = {
 		inherited: false,
 		type: CSS_TYPE_LONGHAND,
 		initial_values: [ "auto" ],
-		other_values: [ "rect(auto,auto,auto,auto)", "rect(3px, 4px, 4em, 0)", "rect(auto, 3em, 4pt, 2px)", "rect(2px 3px 4px 5px)" ],
+		other_values: [ "rect(0 0 0 0)", "rect(auto,auto,auto,auto)", "rect(3px, 4px, 4em, 0)", "rect(auto, 3em, 4pt, 2px)", "rect(2px 3px 4px 5px)" ],
 		invalid_values: [ "rect(auto, 3em, 2%, 5px)" ]
 	},
 	"color": {
 		domProp: "color",
 		inherited: true,
 		type: CSS_TYPE_LONGHAND,
-		initial_values: [ "currentcolor" ],
+		/* XXX should test currentColor, but may or may not be initial */
+		initial_values: [ "black", "#000" ],
 		other_values: [ "green", "#f3c", "#fed292", "rgba(45,300,12,2)", "transparent" ],
 		invalid_values: [ "fff", "ffffff", "#f", "#ff", "#ffff", "#fffff", "#fffffff", "#ffffffff", "#fffffffff" ]
 	},
@@ -887,8 +888,8 @@ var gCSSProperties = {
 		inherited: true,
 		type: CSS_TYPE_TRUE_SHORTHAND,
 		subproperties: [ "list-style-type", "list-style-position", "list-style-image" ],
-		initial_values: [ "none", "outside", "disc", "none disc outside" ],
-		other_values: [ "inside none", "none inside", "none none inside", "none outside none", "square", 'url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACAAAAAgCAIAAAD8GO2jAAAAKElEQVR42u3NQQ0AAAgEoNP+nTWFDzcoQE1udQQCgUAgEAgEAsGTYAGjxAE/G/Q2tQAAAABJRU5ErkJggg==")' ],
+		initial_values: [ "outside", "disc", "none disc outside" ],
+		other_values: [ "inside none", "none inside", "none none inside", "none outside none", "square", 'url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACAAAAAgCAIAAAD8GO2jAAAAKElEQVR42u3NQQ0AAAgEoNP+nTWFDzcoQE1udQQCgUAgEAgEAsGTYAGjxAE/G/Q2tQAAAABJRU5ErkJggg==")', "none" ],
 		invalid_values: []
 	},
 	"list-style-image": {
@@ -1077,7 +1078,7 @@ var gCSSProperties = {
 		domProp: "outlineWidth",
 		inherited: false,
 		type: CSS_TYPE_LONGHAND,
-		/* XXX a value differing from initial requires border-style to be set */
+		prerequisites: { "outline-style": "solid" },
 		initial_values: [ "medium", "3px" ],
 		other_values: [ "thin", "thick", "1px", "2em" ],
 		invalid_values: [ "5%" ]
diff --git a/layout/style/test/test_inherit_computation.html b/layout/style/test/test_inherit_computation.html
new file mode 100644
index 00000000000..487817b8dc1
--- /dev/null
+++ b/layout/style/test/test_inherit_computation.html
@@ -0,0 +1,198 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+-->
+<head>
+  <title>Test for computation of CSS 'inherit'</title>
+  <script type="text/javascript" src="/MochiKit/MochiKit.js"></script>
+  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <script type="text/javascript" src="property_database.js"></script>
+  <style type="text/css" id="stylesheet"></style>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+<p id="display"></p>
+<div id="content" style="display: none">
+
+<div id="testnode"><span id="parent"><span id="child"></span></span></div>
+  
+</div>
+<pre id="test">
+<script class="testbody" type="text/javascript">
+
+/** Test for computation of CSS 'inherit' **/
+
+var gNoComputedStyle = {
+  "-moz-force-broken-image-icon": true,
+  "-moz-margin-end": true,
+  "-moz-margin-start": true,
+  "-moz-padding-end": true,
+  "-moz-padding-start": true,
+  "background-position": true,
+  "content": true,
+  "page-break-after": true,
+  "page-break-before": true,
+  "quotes": true,
+  "clip-path": true,
+  "clip-rule": true,
+  "color-interpolation": true,
+  "color-interpolation-filters": true,
+  "dominant-baseline": true,
+  "fill": true,
+  "fill-opacity": true,
+  "fill-rule": true,
+  "filter": true,
+  "flood-color": true,
+  "flood-opacity": true,
+  "marker": true, // NB: shorthand
+  "marker-end": true,
+  "marker-mid": true,
+  "marker-start": true,
+  "mask": true,
+  "pointer-events": true,
+  "shape-rendering": true,
+  "stop-color": true,
+  "stop-opacity": true,
+  "stroke": true,
+  "stroke-dasharray": true,
+  "stroke-dashoffset": true,
+  "stroke-linecap": true,
+  "stroke-linejoin": true,
+  "stroke-miterlimit": true,
+  "stroke-opacity": true,
+  "stroke-width": true,
+  "text-anchor": true,
+  "text-rendering": true,
+};
+
+function xfail_diffcomputed(property) {
+  return property in gNoComputedStyle;
+}
+
+var gBrokenInherit = {
+  // The nsRuleNode code uses the 'inherit' value for -moz-box-orient
+  "-moz-box-flex": true,
+
+  // Not implemented in nsRuleNode
+  "-moz-border-bottom-colors": true,
+  "-moz-border-left-colors": true,
+  "-moz-border-right-colors": true,
+  "-moz-border-top-colors": true,
+
+  // Parses inherit as a counter name
+  "counter-increment": true,
+  "counter-reset": true,
+};
+
+function xfail_inherit(property, matching_initial) {
+  if (property == "-moz-box-flex" && matching_initial) {
+    // It inherits from the wrong property, but that ends up right in
+    // this case.
+    return false;
+  }
+  return property in gBrokenInherit;
+}
+
+var gParent = document.getElementById("parent");
+var gChild = document.getElementById("child");
+var gStyleSheet = document.getElementById("stylesheet").sheet;
+var gChildRule1 = gStyleSheet.cssRules[gStyleSheet.insertRule("#child {}", gStyleSheet.cssRules.length)];
+var gChildRule2 = gStyleSheet.cssRules[gStyleSheet.insertRule("#child {}", gStyleSheet.cssRules.length)];
+
+// Get the computed value for a property.  For shorthands, return the
+// computed values of all the subproperties, delimited by " ; ".
+function get_computed_value(node, property)
+{
+  var info = gCSSProperties[property];
+  var cs = getComputedStyle(node, "");
+  if (!("subproperties" in info)) {
+    return cs.getPropertyValue(property);
+  }
+  var results = [];
+  for (var idx in info.subproperties) {
+    var subprop = info.subproperties[idx];
+    results.push(cs.getPropertyValue(subprop));
+  }
+  return results.join(" ; ");
+}
+
+function test_property(property)
+{
+  var info = gCSSProperties[property];
+  if (info.backend_only)
+    return;
+
+  if ("prerequisites" in info) {
+    var prereqs = info.prerequisites;
+    for (var prereq in prereqs) {
+      gParent.style.setProperty(prereq, prereqs[prereq], "");
+      gChild.style.setProperty(prereq, prereqs[prereq], "");
+    }
+  }
+
+  if (info.inherited) {
+    gParent.style.setProperty(property, info.initial_values[0], "");
+    var initial_computed = get_computed_value(gChild, property);
+    gChildRule1.style.setProperty(property, info.other_values[0], "");
+    var other_computed = get_computed_value(gChild, property);
+    (xfail_diffcomputed(property) ? todo_isnot : isnot)(
+          other_computed, initial_computed,
+          "should be testing with values that compute to different things " +
+          "for '" + property + "'");
+    gChildRule2.style.setProperty(property, "inherit", "");
+    var inherit_initial_computed = get_computed_value(gChild, property);
+    (xfail_inherit(property, true) ? todo_is : is)(
+       inherit_initial_computed, initial_computed,
+       "inherit should cause inheritance of initial value for '" +
+       property + "'");
+    gParent.style.setProperty(property, info.other_values[0], "");
+    var inherit_other_computed = get_computed_value(gChild, property);
+    (xfail_inherit(property, false) ? todo_is : is)(
+       inherit_other_computed, other_computed,
+       "inherit should cause inheritance of other value for '" +
+       property + "'");
+    gParent.style.removeProperty(property);
+    gChildRule1.style.removeProperty(property);
+    gChildRule2.style.removeProperty(property);
+  } else {
+    gParent.style.setProperty(property, info.other_values[0], "");
+    var initial_computed = get_computed_value(gChild, property);
+    var other_computed = get_computed_value(gParent, property);
+    (xfail_diffcomputed(property) ? todo_isnot : isnot)(
+          other_computed, initial_computed,
+          "should be testing with values that compute to different things " +
+          "for '" + property + "'");
+    gChildRule2.style.setProperty(property, "inherit", "");
+    var inherit_other_computed = get_computed_value(gChild, property);
+    (xfail_inherit(property, false) ? todo_is : is)(
+       inherit_other_computed, other_computed,
+       "inherit should cause inheritance of other value for '" +
+       property + "'");
+    gParent.style.removeProperty(property);
+    gChildRule1.style.setProperty(property, info.other_values[0], "");
+    var inherit_initial_computed = get_computed_value(gChild, property);
+    (xfail_inherit(property, true) ? todo_is : is)(
+       inherit_initial_computed, initial_computed,
+       "inherit should cause inheritance of initial value for '" +
+       property + "'");
+    gParent.style.removeProperty(property);
+    gChildRule1.style.removeProperty(property);
+    gChildRule2.style.removeProperty(property);
+  }
+
+  if ("prerequisites" in info) {
+    var prereqs = info.prerequisites;
+    for (var prereq in prereqs) {
+      gParent.style.removeProperty(prereq);
+      gChild.style.removeProperty(prereq);
+    }
+  }
+}
+
+for (var prop in gCSSProperties)
+  test_property(prop);
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/layout/style/test/test_initial_computation.html b/layout/style/test/test_initial_computation.html
new file mode 100644
index 00000000000..43a60d64c4d
--- /dev/null
+++ b/layout/style/test/test_initial_computation.html
@@ -0,0 +1,270 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+-->
+<head>
+  <title>Test for computation of CSS '-moz-initial'</title>
+  <script type="text/javascript" src="/MochiKit/MochiKit.js"></script>
+  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <script type="text/javascript" src="property_database.js"></script>
+  <style type="text/css" id="stylesheet"></style>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+  <script type="text/javascript">
+  SimpleTest.waitForExplicitFinish();
+
+  var load_count = 0;
+  function load_done() {
+    if (++load_count == 2)
+      run_tests();
+  }
+  </script>
+</head>
+<body>
+<p id="display">
+<iframe id="unstyled" src="unstyled.xml" height="10" width="10" onload="load_done()"></iframe>
+</p>
+<div id="content" style="display: none">
+
+<div id="testnode"><span id="element"></span></div>
+
+  
+</div>
+<pre id="test">
+<script class="testbody" type="text/javascript">
+
+/** Test for computation of CSS '-moz-initial' **/
+
+var gNoComputedStyle = {
+  "-moz-force-broken-image-icon": true,
+  "-moz-margin-end": true,
+  "-moz-margin-start": true,
+  "-moz-padding-end": true,
+  "-moz-padding-start": true,
+  "background-position": true,
+  "content": true,
+  "page-break-after": true,
+  "page-break-before": true,
+  "quotes": true,
+  "clip-path": true,
+  "clip-rule": true,
+  "color-interpolation": true,
+  "color-interpolation-filters": true,
+  "dominant-baseline": true,
+  "fill": true,
+  "fill-opacity": true,
+  "fill-rule": true,
+  "filter": true,
+  "flood-color": true,
+  "flood-opacity": true,
+  "marker": true, // NB: shorthand
+  "marker-end": true,
+  "marker-mid": true,
+  "marker-start": true,
+  "mask": true,
+  "pointer-events": true,
+  "shape-rendering": true,
+  "stop-color": true,
+  "stop-opacity": true,
+  "stroke": true,
+  "stroke-dasharray": true,
+  "stroke-dashoffset": true,
+  "stroke-linecap": true,
+  "stroke-linejoin": true,
+  "stroke-miterlimit": true,
+  "stroke-opacity": true,
+  "stroke-width": true,
+  "text-anchor": true,
+  "text-rendering": true,
+};
+
+function xfail_diffcomputed(property) {
+  return property in gNoComputedStyle;
+}
+
+var gBrokenInitial = {
+  // Presumably either not parsed or not implemented in nsRuleNode.
+  "-moz-appearance": true,
+  "-moz-binding": true,
+  "-moz-border-radius": true,
+  "-moz-border-radius-bottomleft": true,
+  "-moz-border-radius-bottomright": true,
+  "-moz-border-radius-topleft": true,
+  "-moz-border-radius-topright": true,
+  "-moz-box-align": true,
+  "-moz-box-direction": true,
+  "-moz-box-flex": true,
+  "-moz-box-orient": true,
+  "-moz-box-pack": true,
+  "-moz-box-sizing": true,
+  "-moz-column-count": true,
+  "-moz-column-gap": true,
+  "-moz-column-width": true,
+  "-moz-float-edge": true,
+  "-moz-image-region": true,
+  "-moz-outline-radius": true,
+  "-moz-outline-radius-bottomleft": true,
+  "-moz-outline-radius-bottomright": true,
+  "-moz-outline-radius-topleft": true,
+  "-moz-outline-radius-topright": true,
+  "-moz-user-focus": true,
+  "-moz-user-input": true,
+  "-moz-user-modify": true,
+  "-moz-user-select": true,
+  "background-attachment": true,
+  "background-color": true,
+  "background-image": true,
+  "background-repeat": true,
+  // XXX Why aren't the border-width values failing, etc.?
+  "border-bottom-color": true,
+  "border-collapse": true,
+  "border-color": true,
+  "border-left-color": true,
+  "border-right-color": true,
+  "border-spacing": true,
+  "border-top-color": true,
+  "bottom": true,
+  "caption-side": true,
+  "clear": true,
+  "cursor": true,
+  "direction": true,
+  "display": true,
+  "empty-cells": true,
+  "font": true, // XXX This one is weird.
+  "font-family": true, // XXX This one is weird.
+  "height": true,
+  "left": true,
+  "letter-spacing": true,
+  "line-height": true,
+  "list-style": true,
+  "list-style-image": true,
+  "list-style-position": true,
+  "list-style-type": true,
+  "margin": true,
+  "margin-bottom": true,
+  "margin-left": true,
+  "margin-right": true,
+  "margin-top": true,
+  "max-height": true,
+  "max-width": true,
+  "min-height": true,
+  "min-width": true,
+  "opacity": true,
+  "outline": true,
+  "outline-color": true, // XXX Why didn't this fail until I added the if (info.inherited) checks?
+  "outline-offset": true,
+  "outline-style": true,
+  "overflow": true,
+  "padding": true,
+  "padding-bottom": true,
+  "padding-left": true,
+  "padding-right": true,
+  "padding-top": true,
+  "position": true,
+  "right": true,
+  "table-layout": true,
+  "text-decoration": true,
+  "text-indent": true,
+  "text-transform": true,
+  "top": true,
+  "unicode-bidi": true,
+  "vertical-align": true,
+  "visibility": true,
+  "white-space": true,
+  "width": true,
+  "word-spacing": true,
+  "z-index": true,
+};
+
+function xfail_initial(property) {
+  return property in gBrokenInitial;
+}
+
+var gElement = document.getElementById("element");
+var gStyleSheet = document.getElementById("stylesheet").sheet;
+var gRule1 = gStyleSheet.cssRules[gStyleSheet.insertRule("#element {}", gStyleSheet.cssRules.length)];
+var gRule2 = gStyleSheet.cssRules[gStyleSheet.insertRule("#element {}", gStyleSheet.cssRules.length)];
+
+var gInitialValues;
+var gInitialPrereqsRule;
+
+function setup_initial_values() {
+  var iframe = document.getElementById("unstyled");
+  gInitialValues = iframe.contentWindow.getComputedStyle(
+                     iframe.contentDocument.documentElement.firstChild, "");
+  var sheet = iframe.contentDocument.styleSheets[0];
+  gInitialPrereqsRule = sheet.cssRules[sheet.insertRule(":root > * {}", sheet.cssRules.length)];
+}
+
+// Get the computed value for a property.  For shorthands, return the
+// computed values of all the subproperties, delimited by " ; ".
+function get_computed_value(cs, property)
+{
+  var info = gCSSProperties[property];
+  if (!("subproperties" in info)) {
+    return cs.getPropertyValue(property);
+  }
+  var results = [];
+  for (var idx in info.subproperties) {
+    var subprop = info.subproperties[idx];
+    results.push(cs.getPropertyValue(subprop));
+  }
+  return results.join(" ; ");
+}
+
+function test_property(property)
+{
+  var info = gCSSProperties[property];
+  if (info.backend_only)
+    return;
+
+  if ("prerequisites" in info) {
+    var prereqs = info.prerequisites;
+    for (var prereq in prereqs) {
+      gElement.style.setProperty(prereq, prereqs[prereq], "");
+      gInitialPrereqsRule.style.setProperty(prereq, prereqs[prereq], "");
+    }
+  }
+  if (info.inherited) {
+    gElement.parentNode.style.setProperty(property, info.other_values[0], "");
+  }
+
+  var initial_computed = get_computed_value(gInitialValues, property);
+  gRule1.style.setProperty(property, info.other_values[0], "");
+  var other_computed = get_computed_value(getComputedStyle(gElement, ""), property);
+  (xfail_diffcomputed(property) ? todo_isnot : isnot)(
+        other_computed, initial_computed,
+        "should be testing with values that compute to different things " +
+        "for '" + property + "'");
+  gRule2.style.setProperty(property, "-moz-initial", "");
+  var initial_val_computed = get_computed_value(getComputedStyle(gElement, ""), property);
+  (xfail_initial(property) ? todo_is : is)(
+     initial_val_computed, initial_computed,
+     "-moz-initial should cause initial value for '" + property + "'");
+  gRule1.style.removeProperty(property);
+  gRule2.style.removeProperty(property);
+
+  if ("prerequisites" in info) {
+    var prereqs = info.prerequisites;
+    for (var prereq in prereqs) {
+      gElement.style.removeProperty(prereq);
+      gInitialPrereqsRule.style.removeProperty(prereq);
+    }
+  }
+  if (info.inherited) {
+    gElement.parentNode.style.removeProperty(property);
+  }
+}
+
+function run_tests() {
+  setup_initial_values();
+  for (var prop in gCSSProperties)
+    test_property(prop);
+  SimpleTest.finish();
+}
+
+load_done();
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/layout/style/test/test_value_computation.html b/layout/style/test/test_value_computation.html
new file mode 100644
index 00000000000..d11f5a5e313
--- /dev/null
+++ b/layout/style/test/test_value_computation.html
@@ -0,0 +1,292 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+-->
+<head>
+  <title>Test for computation of values in property database</title>
+  <script type="text/javascript" src="/MochiKit/MochiKit.js"></script>
+  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <script type="text/javascript" src="property_database.js"></script>
+  <style type="text/css" id="stylesheet"></style>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+  <script type="text/javascript">
+  SimpleTest.waitForExplicitFinish();
+
+  var load_count = 0;
+  function load_done() {
+    if (++load_count == 2)
+      run_tests();
+  }
+  </script>
+</head>
+<body>
+<p id="display">
+<iframe id="unstyled" src="unstyled.xml" height="10" width="10" onload="load_done()"></iframe>
+</p>
+<div id="content" style="display: none">
+
+<div id="testnode"><span id="element"></span></div>
+
+  
+</div>
+<pre id="test">
+<script class="testbody" type="text/javascript">
+
+/** Test for computation of values in property database **/
+
+var gNoComputedStyle = {
+  "-moz-force-broken-image-icon": true,
+  "-moz-margin-end": true,
+  "-moz-margin-start": true,
+  "-moz-padding-end": true,
+  "-moz-padding-start": true,
+  "background-position": true,
+  "content": true,
+  "page-break-after": true,
+  "page-break-before": true,
+  "quotes": true,
+  "clip-path": true,
+  "clip-rule": true,
+  "color-interpolation": true,
+  "color-interpolation-filters": true,
+  "dominant-baseline": true,
+  "fill": true,
+  "fill-opacity": true,
+  "fill-rule": true,
+  "filter": true,
+  "flood-color": true,
+  "flood-opacity": true,
+  "marker": true, // NB: shorthand
+  "marker-end": true,
+  "marker-mid": true,
+  "marker-start": true,
+  "mask": true,
+  "pointer-events": true,
+  "shape-rendering": true,
+  "stop-color": true,
+  "stop-opacity": true,
+  "stroke": true,
+  "stroke-dasharray": true,
+  "stroke-dashoffset": true,
+  "stroke-linecap": true,
+  "stroke-linejoin": true,
+  "stroke-miterlimit": true,
+  "stroke-opacity": true,
+  "stroke-width": true,
+  "text-anchor": true,
+  "text-rendering": true,
+};
+
+function xfail_diffcomputed(property) {
+  return property in gNoComputedStyle;
+}
+
+var gNotAccepted = {
+  "-moz-column-width": [ "50%" ],
+  "-moz-user-select": [ "auto" ],
+  "background-color": [ "rgb(255.0,0.387,3489)" ],
+  "content": [ "none" ],
+  "cue": [ "none none", "none url(404.wav)" ],
+  "list-style": [ "none disc outside" ],
+  "speak-punctuation": [ "none" ],
+};
+
+var gBackgroundValuesWithOnlyPosition = {
+  "top": true,
+  "left": true,
+  "50% 50%": true,
+  "center": true,
+  "bottom right scroll none transparent repeat": true,
+  "50% transparent": true,
+  "transparent 50%": true,
+  "50%": true,
+};
+
+var gBadComputed = {
+  // NS_STYLE_COLUMN_COUNT_AUTO is 0
+  "-moz-column-count": [ "0" ],
+
+  "clip": [ "rect(auto,auto,auto,auto)" ],
+
+  // This seems really broken!
+  "counter-increment": [ "none" ],
+  "counter-reset": [ "none" ],
+
+  // So does this.
+  "marker-offset": [ "auto" ],
+
+  // No idea what's happening for these two either
+  "border-bottom": [ "thin" ],
+  "outline-width": [ "3px" ],
+
+  // Something wrong with our alpha-component parsing or clamping.
+  "background-color": [ "rgba(255,255,255,-3.7)" ],
+
+  // 'normal' should compute to 0
+  "word-spacing": [ "0", "0px", "-0em" ],
+
+  // These are probably bogus tests...
+  "-moz-outline-radius": [ "0%" ],
+  "-moz-outline-radius-bottomleft": [ "0%" ],
+  "-moz-outline-radius-bottomright": [ "0%" ],
+  "-moz-outline-radius-topleft": [ "0%" ],
+  "-moz-outline-radius-topright": [ "0%" ],
+  "margin": [ "0% 0px 0em 0pt" ],
+  "margin-bottom": [ "0%" ],
+  "margin-left": [ "0%" ],
+  "margin-right": [ "0%" ],
+  "margin-top": [ "0%" ],
+  "padding": [ "0% 0px 0em 0pt" ],
+  "padding-bottom": [ "0%" ],
+  "padding-left": [ "0%" ],
+  "padding-right": [ "0%" ],
+  "padding-top": [ "0%" ],
+};
+
+function xfail_value(property, value, is_initial) {
+  if (property in gNoComputedStyle)
+    return !is_initial;
+
+  if ((property in gNotAccepted) &&
+      gNotAccepted[property].indexOf(value) != -1)
+    return true;
+
+  if ((property in gBadComputed) &&
+      gBadComputed[property].indexOf(value) != -1)
+    return true;
+
+  // One subproperty of 'background' is in gNoComputedStyle
+  if (property == "background" && value in gBackgroundValuesWithOnlyPosition)
+    return true;
+
+  return false;
+}
+
+var gElement = document.getElementById("element");
+var gStyleSheet = document.getElementById("stylesheet").sheet;
+var gRule1 = gStyleSheet.cssRules[gStyleSheet.insertRule("#element {}", gStyleSheet.cssRules.length)];
+var gRule2 = gStyleSheet.cssRules[gStyleSheet.insertRule("#element {}", gStyleSheet.cssRules.length)];
+
+var gInitialValues;
+var gInitialPrereqsRule;
+
+function setup_initial_values() {
+  var iframe = document.getElementById("unstyled");
+  gInitialValues = iframe.contentWindow.getComputedStyle(
+                     iframe.contentDocument.documentElement.firstChild, "");
+  var sheet = iframe.contentDocument.styleSheets[0];
+  gInitialPrereqsRule = sheet.cssRules[sheet.insertRule(":root > * {}", sheet.cssRules.length)];
+}
+
+// Get the computed value for a property.  For shorthands, return the
+// computed values of all the subproperties, delimited by " ; ".
+function get_computed_value(cs, property)
+{
+  var info = gCSSProperties[property];
+  if (!("subproperties" in info)) {
+    return cs.getPropertyValue(property);
+  }
+  var results = [];
+  for (var idx in info.subproperties) {
+    var subprop = info.subproperties[idx];
+    results.push(cs.getPropertyValue(subprop));
+  }
+  return results.join(" ; ");
+}
+
+function test_value(property, val, is_initial)
+{
+  var info = gCSSProperties[property];
+  if (info.backend_only)
+    return;
+
+  if ("prerequisites" in info) {
+    var prereqs = info.prerequisites;
+    for (var prereq in prereqs) {
+      gElement.style.setProperty(prereq, prereqs[prereq], "");
+      gInitialPrereqsRule.style.setProperty(prereq, prereqs[prereq], "");
+    }
+  }
+  if (info.inherited && is_initial) {
+    gElement.parentNode.style.setProperty(property, info.other_values[0], "");
+  }
+
+  var initial_computed = get_computed_value(gInitialValues, property);
+  if (is_initial) {
+    gRule1.style.setProperty(property, info.other_values[0], "");
+    var other_computed = get_computed_value(getComputedStyle(gElement, ""), property);
+    (xfail_diffcomputed(property) ? todo_isnot : isnot)(
+          other_computed, initial_computed,
+          "should be testing with values that compute to different things " +
+          "for '" + property + "'");
+  }
+  gRule2.style.setProperty(property, val, "");
+  var val_computed = get_computed_value(getComputedStyle(gElement, ""), property);
+  if (is_initial) {
+    (xfail_value(property, val, is_initial) ? todo_is : is)(
+       val_computed, initial_computed,
+       "should get initial value for '" + property + ":" + val + "'");
+  } else {
+    (xfail_value(property, val, is_initial) ? todo_isnot : isnot)(
+       val_computed, initial_computed,
+       "should not get initial value for '" + property + ":" + val + "'");
+  }
+  if (is_initial)
+    gRule1.style.removeProperty(property);
+  gRule2.style.removeProperty(property);
+
+  if ("prerequisites" in info) {
+    var prereqs = info.prerequisites;
+    for (var prereq in prereqs) {
+      gElement.style.removeProperty(prereq);
+      gInitialPrereqsRule.style.removeProperty(prereq);
+    }
+  }
+  if (info.inherited && is_initial) {
+    gElement.parentNode.style.removeProperty(property);
+  }
+}
+
+function test_property(prop) {
+  var info = gCSSProperties[prop];
+  for (var idx in info.initial_values)
+    test_value(prop, info.initial_values[idx], true);
+  for (var idx in info.other_values)
+    test_value(prop, info.other_values[idx], false);
+}
+
+function run_tests() {
+  setup_initial_values();
+  var props = [];
+  for (var prop in gCSSProperties)
+    props.push(prop);
+  props = props.reverse();
+  function do_one(l) {
+    if (l.length == 0) {
+      // SimpleTest.finish() is really slow, so we have to disable the
+      // slow script dialog for this part
+      netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");
+      var prefService = Components.classes["@mozilla.org/preferences-service;1"].
+                          getService(Components.interfaces.nsIPrefService);
+      var domBranch = prefService.getBranch("dom.");
+      var oldVal = domBranch.getIntPref("max_script_run_time");
+      domBranch.setIntPref("max_script_run_time", 0);
+
+      SimpleTest.finish();
+
+      domBranch.setIntPref("max_script_run_time", oldVal);
+
+      return;
+    }
+    test_property(l.pop());
+    setTimeout(do_one, 0, l);
+  }
+  setTimeout(do_one, 0, props);
+}
+
+load_done();
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/layout/style/test/unstyled.css b/layout/style/test/unstyled.css
new file mode 100644
index 00000000000..82767f9b2f6
--- /dev/null
+++ b/layout/style/test/unstyled.css
@@ -0,0 +1,2 @@
+/* we're testing computed style on elements without frames */
+root { display: none }
diff --git a/layout/style/test/unstyled.xml b/layout/style/test/unstyled.xml
new file mode 100644
index 00000000000..86b7c54acd4
--- /dev/null
+++ b/layout/style/test/unstyled.xml
@@ -0,0 +1,3 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="unstyled.css" type="text/css"?>
+<root><child/></root>