--- a/layout/style/test/test_media_queries.html
+++ b/layout/style/test/test_media_queries.html
@@ -178,24 +178,36 @@ function run() {
            "Media query '" + q + "' should " + (should_apply ? "" : "NOT ") +
            "apply after cloning");
       }
     });
   }
 
   // The no-type syntax doesn't mix with the not and only keywords.
   query_should_be_parseable("(orientation)");
-  query_should_not_be_parseable("not (orientation)");
+  query_should_be_parseable("not (orientation)");
   query_should_not_be_parseable("only (orientation)");
   query_should_be_parseable("all and (orientation)");
   query_should_be_parseable("not all and (orientation)");
   query_should_be_parseable("only all and (orientation)");
 
+  query_should_not_be_parseable("not not (orientation)");
+  query_should_be_parseable("(orientation) and (orientation)");
+  query_should_be_parseable("(orientation) or (orientation)");
+  query_should_be_parseable("(orientation) or ((orientation) and ((orientation) or (orientation) or (not (orientation))))");
+
+  query_should_not_be_parseable("all and (orientation) or (orientation)");
+  query_should_be_parseable("all and (orientation) and (orientation)");
+
+  query_should_not_be_parseable("(orientation) and (orientation) or (orientation)");
+  query_should_not_be_parseable("(orientation) and not (orientation)");
+
+
   query_should_be_parseable("(-moz-device-orientation)");
-  query_should_not_be_parseable("not (-moz-device-orientation)");
+  query_should_be_parseable("not (-moz-device-orientation)");
   query_should_not_be_parseable("only (-moz-device-orientation)");
   query_should_be_parseable("all and (-moz-device-orientation)");
   query_should_be_parseable("not all and (-moz-device-orientation)");
   query_should_be_parseable("only all and (-moz-device-orientation)");
 
   // Test that the 'not', 'only', 'and', and 'or' keywords are not
   // allowed as media types.
   query_should_not_be_parseable("not");
@@ -225,38 +237,47 @@ function run() {
   query_should_be_parseable("not unknowntype and (width)");
   query_should_not_be_parseable("only not and (width)");
   query_should_not_be_parseable("only and and (width)");
   query_should_not_be_parseable("only or and (width)");
   query_should_not_be_parseable("only only and (width)");
   query_should_be_parseable("only unknowntype and (width)");
 
   var features = [ "width", "height", "device-width", "device-height" ];
+  var separators = [ ":", ">", ">=", "=", "<=", "<" ];
+
   var feature;
   var i;
   for (i in features) {
     feature = features[i];
     expression_should_be_parseable(feature);
-    expression_should_be_parseable(feature + ": 0");
-    expression_should_be_parseable(feature + ": 0px");
-    expression_should_be_parseable(feature + ": 0em");
-    expression_should_be_parseable(feature + ": -0");
-    expression_should_be_parseable("min-" + feature + ": -0");
-    expression_should_be_parseable("max-" + feature + ": -0");
-    expression_should_be_parseable(feature + ": -0cm");
-    expression_should_be_parseable(feature + ": 1px");
-    expression_should_be_parseable(feature + ": 0.001mm");
-    expression_should_be_parseable(feature + ": 100000px");
-    expression_should_not_be_parseable(feature + ": -1px");
-    expression_should_not_be_parseable("min-" + feature + ": -1px");
-    expression_should_not_be_parseable("max-" + feature + ": -1px");
-    expression_should_not_be_parseable(feature + ": -0.00001mm");
-    expression_should_not_be_parseable(feature + ": -100000em");
     expression_should_not_be_parseable("min-" + feature);
     expression_should_not_be_parseable("max-" + feature);
+    for (let separator of separators) {
+      expression_should_be_parseable(feature + " " + separator + " 0");
+      expression_should_be_parseable(feature + " " + separator + " 0px");
+      expression_should_be_parseable(feature + " " + separator + " 0em");
+      expression_should_be_parseable(feature + " " + separator + " -0");
+      expression_should_be_parseable(feature + " " + separator + " -0cm");
+      expression_should_be_parseable(feature + " " + separator + " 1px");
+      expression_should_be_parseable(feature + " " + separator + " 0.001mm");
+      expression_should_be_parseable(feature + " " + separator + " 100000px");
+      if (separator == ":") {
+        expression_should_be_parseable("min-" + feature + " " + separator + " -0");
+        expression_should_be_parseable("max-" + feature + " " + separator + " -0");
+      } else {
+        expression_should_not_be_parseable("min-" + feature + " " + separator + " -0");
+        expression_should_not_be_parseable("max-" + feature + " " + separator + " -0");
+      }
+      expression_should_not_be_parseable(feature + " " + separator + " -1px");
+      expression_should_not_be_parseable("min-" + feature + " " + separator + " -1px");
+      expression_should_not_be_parseable("max-" + feature + " " + separator + " -1px");
+      expression_should_not_be_parseable(feature + " " + separator + " -0.00001mm");
+      expression_should_not_be_parseable(feature + " " + separator + " -100000em");
+    }
   }
 
   var mediatypes = ["browser", "minimal-ui", "standalone", "fullscreen"];
 
   mediatypes.forEach(function(type) {
     expression_should_be_parseable("display-mode: " + type);
   });
 
@@ -271,25 +292,31 @@ function run() {
   var width_val = 117; // pick two not-too-round numbers
   var height_val = 76;
   change_state(function() {
     iframe_style.width = width_val + "px";
     iframe_style.height = height_val + "px";
   });
   var device_width = window.screen.width;
   var device_height = window.screen.height;
-  features = { "width": width_val,
-                    "height": height_val,
-                    "device-width": device_width,
-                    "device-height": device_height };
+  features = {
+    "width": width_val,
+    "height": height_val,
+    "device-width": device_width,
+    "device-height": device_height
+  };
   for (feature in features) {
     var value = features[feature];
     should_apply("all and (" + feature + ": " + value + "px)");
+    should_apply("all and (" + feature + " = " + value + "px)");
     should_not_apply("all and (" + feature + ": " + (value + 1) + "px)");
     should_not_apply("all and (" + feature + ": " + (value - 1) + "px)");
+    should_not_apply("all and (" + feature + " = " + (value + 1) + "px)");
+    should_not_apply("all and (" + feature + " = " + (value - 1) + "px)");
+
     should_apply("all and (min-" + feature + ": " + value + "px)");
     should_not_apply("all and (min-" + feature + ": " + (value + 1) + "px)");
     should_apply("all and (min-" + feature + ": " + (value - 1) + "px)");
     should_apply("all and (max-" + feature + ": " + value + "px)");
     should_apply("all and (max-" + feature + ": " + (value + 1) + "px)");
     should_not_apply("all and (max-" + feature + ": " + (value - 1) + "px)");
     should_not_apply("all and (min-" + feature + ": " +
                      (Math.ceil(value/em_size) + 1) + "em)");
@@ -302,16 +329,31 @@ function run() {
     should_not_apply("all and (min-" + feature + ": " +
                      (Math.ceil(value/em_size) + 1) + "rem)");
     should_apply("all and (min-" + feature + ": " +
                  (Math.floor(value/em_size) - 1) + "rem)");
     should_apply("all and (max-" + feature + ": " +
                  (Math.ceil(value/em_size) + 1) + "rem)");
     should_not_apply("all and (max-" + feature + ": " +
                      (Math.floor(value/em_size) - 1) + "rem)");
+
+    should_apply("(" + feature + " <= " + value + "px)");
+    should_apply("(" + feature + " >= " + value + "px)");
+    should_not_apply("(" + feature + " < " + value + "px)");
+    should_not_apply("(" + feature + " > " + value + "px)");
+
+    should_apply("(" + feature + " < " + (value + 1) + "px)");
+    should_apply("(" + feature + " <= " + (value + 1) + "px)");
+    should_not_apply("(" + feature + " > " + (value + 1) + "px)");
+    should_not_apply("(" + feature + " >= " + (value + 1) + "px)");
+
+    should_apply("(" + feature + " > " + (value - 1) + "px)");
+    should_apply("(" + feature + " >= " + (value - 1) + "px)");
+    should_not_apply("(" + feature + " < " + (value - 1) + "px)");
+    should_not_apply("(" + feature + " <= " + (value - 1) + "px)");
   }
 
   change_state(function() {
     iframe_style.width = "0";
   });
   should_apply("all and (height)");
   should_not_apply("all and (width)");
   change_state(function() {

--- a/testing/web-platform/meta/html/semantics/embedded-content/the-img-element/sizes/parse-a-sizes-attribute.html.ini
+++ b/testing/web-platform/meta/html/semantics/embedded-content/the-img-element/sizes/parse-a-sizes-attribute.html.ini
@@ -1,15 +1,12 @@
 [parse-a-sizes-attribute.html]
   [<img srcset="/images/green-1x1.png?e38 50w, /images/green-16x16.png?e38 51w" sizes="(min-width:calc(0)) 1px"> ref sizes="1px" (standards mode)]
     expected: FAIL
 
-  [<img srcset="/images/green-1x1.png?e57 50w, /images/green-16x16.png?e57 51w" sizes="(min-width:0) or (min-width:0) 1px"> ref sizes="1px" (standards mode)]
-    expected: FAIL
-
   [<img srcset="/images/green-1x1.png?e58 50w, /images/green-16x16.png?e58 51w" sizes="(min-width:0) or (unknown-mf-name) 1px"> ref sizes="1px" (standards mode)]
     expected: FAIL
 
   [<img srcset="/images/green-1x1.png?e59 50w, /images/green-16x16.png?e59 51w" sizes="(min-width:0) or (min-width:unknown-mf-value) 1px"> ref sizes="1px" (standards mode)]
     expected: FAIL
 
   [<img srcset="/images/green-1x1.png?e60 50w, /images/green-16x16.png?e60 51w" sizes="(min-width:0) or (min-width:-1px) 1px"> ref sizes="1px" (standards mode)]
     expected: FAIL
@@ -27,19 +24,16 @@
     expected: FAIL
 
   [<img srcset="/images/green-1x1.png?f49 50w, /images/green-16x16.png?f49 51w" sizes="(min-width:0) calc(1px"> ref sizes="100vw" (standards mode)]
     expected: FAIL
 
   [<img srcset="/images/green-1x1.png?e38 50w, /images/green-16x16.png?e38 51w" sizes="(min-width:calc(0)) 1px"> ref sizes="1px" (quirks mode)]
     expected: FAIL
 
-  [<img srcset="/images/green-1x1.png?e57 50w, /images/green-16x16.png?e57 51w" sizes="(min-width:0) or (min-width:0) 1px"> ref sizes="1px" (quirks mode)]
-    expected: FAIL
-
   [<img srcset="/images/green-1x1.png?e58 50w, /images/green-16x16.png?e58 51w" sizes="(min-width:0) or (unknown-mf-name) 1px"> ref sizes="1px" (quirks mode)]
     expected: FAIL
 
   [<img srcset="/images/green-1x1.png?e59 50w, /images/green-16x16.png?e59 51w" sizes="(min-width:0) or (min-width:unknown-mf-value) 1px"> ref sizes="1px" (quirks mode)]
     expected: FAIL
 
   [<img srcset="/images/green-1x1.png?e60 50w, /images/green-16x16.png?e60 51w" sizes="(min-width:0) or (min-width:-1px) 1px"> ref sizes="1px" (quirks mode)]
     expected: FAIL
@@ -57,19 +51,16 @@
     expected: FAIL
 
   [<img srcset="/images/green-1x1.png?f49 50w, /images/green-16x16.png?f49 51w" sizes="(min-width:0) calc(1px"> ref sizes="100vw" (quirks mode)]
     expected: FAIL
 
   [<img srcset="/images/green-1x1.png?e38 50w, /images/green-16x16.png?e38 51w" sizes="(min-width:calc(0)) 1px"> ref sizes="1px" (display:none)]
     expected: FAIL
 
-  [<img srcset="/images/green-1x1.png?e57 50w, /images/green-16x16.png?e57 51w" sizes="(min-width:0) or (min-width:0) 1px"> ref sizes="1px" (display:none)]
-    expected: FAIL
-
   [<img srcset="/images/green-1x1.png?e58 50w, /images/green-16x16.png?e58 51w" sizes="(min-width:0) or (unknown-mf-name) 1px"> ref sizes="1px" (display:none)]
     expected: FAIL
 
   [<img srcset="/images/green-1x1.png?e59 50w, /images/green-16x16.png?e59 51w" sizes="(min-width:0) or (min-width:unknown-mf-value) 1px"> ref sizes="1px" (display:none)]
     expected: FAIL
 
   [<img srcset="/images/green-1x1.png?e60 50w, /images/green-16x16.png?e60 51w" sizes="(min-width:0) or (min-width:-1px) 1px"> ref sizes="1px" (display:none)]
     expected: FAIL
@@ -87,19 +78,16 @@
     expected: FAIL
 
   [<img srcset="/images/green-1x1.png?f49 50w, /images/green-16x16.png?f49 51w" sizes="(min-width:0) calc(1px"> ref sizes="100vw" (display:none)]
     expected: FAIL
 
   [<img srcset="/images/green-1x1.png?e38 50w, /images/green-16x16.png?e38 51w" sizes="(min-width:calc(0)) 1px"> ref sizes="1px" (width:1000px)]
     expected: FAIL
 
-  [<img srcset="/images/green-1x1.png?e57 50w, /images/green-16x16.png?e57 51w" sizes="(min-width:0) or (min-width:0) 1px"> ref sizes="1px" (width:1000px)]
-    expected: FAIL
-
   [<img srcset="/images/green-1x1.png?e58 50w, /images/green-16x16.png?e58 51w" sizes="(min-width:0) or (unknown-mf-name) 1px"> ref sizes="1px" (width:1000px)]
     expected: FAIL
 
   [<img srcset="/images/green-1x1.png?e59 50w, /images/green-16x16.png?e59 51w" sizes="(min-width:0) or (min-width:unknown-mf-value) 1px"> ref sizes="1px" (width:1000px)]
     expected: FAIL
 
   [<img srcset="/images/green-1x1.png?e60 50w, /images/green-16x16.png?e60 51w" sizes="(min-width:0) or (min-width:-1px) 1px"> ref sizes="1px" (width:1000px)]
     expected: FAIL

--- a/testing/web-platform/tests/css/mediaqueries/test_media_queries.html
+++ b/testing/web-platform/tests/css/mediaqueries/test_media_queries.html
@@ -94,82 +94,123 @@ function run() {
     function expression_should_not_be_parseable(e) {
       test(function() {
         assert_false(expression_is_parseable(e));
       }, "subtest_" + ++testNum, {assert: "expression " + e + " should not be parseable"});
     }
 
     // The no-type syntax doesn't mix with the not and only keywords.
     query_should_be_parseable("(orientation)");
-    query_should_not_be_parseable("not (orientation)");
+    query_should_be_parseable("not (orientation)");
     query_should_not_be_parseable("only (orientation)");
     query_should_be_parseable("all and (orientation)");
     query_should_be_parseable("not all and (orientation)");
     query_should_be_parseable("only all and (orientation)");
 
+    query_should_not_be_parseable("not not (orientation)");
+    query_should_be_parseable("(orientation) and (orientation)");
+    query_should_be_parseable("(orientation) or (orientation)");
+    query_should_be_parseable("(orientation) or ((orientation) and ((orientation) or (orientation) or (not (orientation))))");
+
+    query_should_not_be_parseable("all and (orientation) or (orientation)");
+    query_should_be_parseable("all and (orientation) and (orientation)");
+
+    query_should_not_be_parseable("(orientation) and (orientation) or (orientation)");
+    query_should_not_be_parseable("(orientation) and not (orientation)");
+
+
     var features = [ "width", "height", "device-width", "device-height" ];
+    var separators = [ ":", ">", ">=", "=", "<=", "<" ];
     var feature;
     var i;
     for (i in features) {
       feature = features[i];
       expression_should_be_parseable(feature);
-      expression_should_be_parseable(feature + ": 0");
-      expression_should_be_parseable(feature + ": 0px");
-      expression_should_be_parseable(feature + ": 0em");
-      expression_should_be_parseable(feature + ": -0");
-      expression_should_be_parseable("min-" + feature + ": -0");
-      expression_should_be_parseable("max-" + feature + ": -0");
-      expression_should_be_parseable(feature + ": -0cm");
-      expression_should_be_parseable(feature + ": 1px");
-      expression_should_be_parseable(feature + ": 0.001mm");
-      expression_should_be_parseable(feature + ": 100000px");
-      expression_should_not_be_parseable(feature + ": -1px");
-      expression_should_not_be_parseable("min-" + feature + ": -1px");
-      expression_should_not_be_parseable("max-" + feature + ": -1px");
-      expression_should_not_be_parseable(feature + ": -0.00001mm");
-      expression_should_not_be_parseable(feature + ": -100000em");
       expression_should_not_be_parseable("min-" + feature);
       expression_should_not_be_parseable("max-" + feature);
+      for (let separator of separators) {
+        expression_should_be_parseable(feature + " " + separator + " 0");
+        expression_should_be_parseable(feature + " " + separator + " 0px");
+        expression_should_be_parseable(feature + " " + separator + " 0em");
+        expression_should_be_parseable(feature + " " + separator + " -0");
+        expression_should_be_parseable(feature + " " + separator + " -0cm");
+        expression_should_be_parseable(feature + " " + separator + " 1px");
+        expression_should_be_parseable(feature + " " + separator + " 0.001mm");
+        expression_should_be_parseable(feature + " " + separator + " 100000px");
+        if (separator == ":") {
+          expression_should_be_parseable("min-" + feature + " " + separator + " -0");
+          expression_should_be_parseable("max-" + feature + " " + separator + " -0");
+        } else {
+          expression_should_not_be_parseable("min-" + feature + " " + separator + " -0");
+          expression_should_not_be_parseable("max-" + feature + " " + separator + " -0");
+        }
+        expression_should_not_be_parseable(feature + " " + separator + " -1px");
+        expression_should_not_be_parseable("min-" + feature + " " + separator + " -1px");
+        expression_should_not_be_parseable("max-" + feature + " " + separator + " -1px");
+        expression_should_not_be_parseable(feature + " " + separator + " -0.00001mm");
+        expression_should_not_be_parseable(feature + " " + separator + " -100000em");
+      }
     }
 
     var content_div = document.getElementById("content");
     content_div.style.font = "medium sans-serif";
     var em_size =
       getComputedStyle(content_div, "").fontSize.match(/^(\d+)px$/)[1];
 
     // in this test, assume the common underlying implementation is correct
     var width_val = 117; // pick two not-too-round numbers
     var height_val = 76;
     iframe_style.width = width_val + "px";
     iframe_style.height = height_val + "px";
     var device_width = window.screen.width;
     var device_height = window.screen.height;
-    features = { "width": width_val,
-                      "height": height_val,
-                      "device-width": device_width,
-                      "device-height": device_height };
+    features = {
+      "width": width_val,
+      "height": height_val,
+      "device-width": device_width,
+      "device-height": device_height
+    };
     for (feature in features) {
       var value = features[feature];
       should_apply("all and (" + feature + ": " + value + "px)");
+      should_apply("all and (" + feature + " = " + value + "px)");
       should_not_apply("all and (" + feature + ": " + (value + 1) + "px)");
       should_not_apply("all and (" + feature + ": " + (value - 1) + "px)");
+      should_not_apply("all and (" + feature + " = " + (value + 1) + "px)");
+      should_not_apply("all and (" + feature + " = " + (value - 1) + "px)");
+
       should_apply("all and (min-" + feature + ": " + value + "px)");
       should_not_apply("all and (min-" + feature + ": " + (value + 1) + "px)");
       should_apply("all and (min-" + feature + ": " + (value - 1) + "px)");
       should_apply("all and (max-" + feature + ": " + value + "px)");
       should_apply("all and (max-" + feature + ": " + (value + 1) + "px)");
       should_not_apply("all and (max-" + feature + ": " + (value - 1) + "px)");
       should_not_apply("all and (min-" + feature + ": " +
                        (Math.ceil(value/em_size) + 1) + "em)");
       should_apply("all and (min-" + feature + ": " +
                    (Math.floor(value/em_size) - 1) + "em)");
       should_apply("all and (max-" + feature + ": " +
                    (Math.ceil(value/em_size) + 1) + "em)");
       should_not_apply("all and (max-" + feature + ": " +
                        (Math.floor(value/em_size) - 1) + "em)");
+
+      should_apply("(" + feature + " <= " + value + "px)");
+      should_apply("(" + feature + " >= " + value + "px)");
+      should_not_apply("(" + feature + " < " + value + "px)");
+      should_not_apply("(" + feature + " > " + value + "px)");
+
+      should_apply("(" + feature + " < " + (value + 1) + "px)");
+      should_apply("(" + feature + " <= " + (value + 1) + "px)");
+      should_not_apply("(" + feature + " > " + (value + 1) + "px)");
+      should_not_apply("(" + feature + " >= " + (value + 1) + "px)");
+
+      should_apply("(" + feature + " > " + (value - 1) + "px)");
+      should_apply("(" + feature + " >= " + (value - 1) + "px)");
+      should_not_apply("(" + feature + " < " + (value - 1) + "px)");
+      should_not_apply("(" + feature + " <= " + (value - 1) + "px)");
     }
 
     iframe_style.width = "0";
     should_apply("all and (height)");
     should_not_apply("all and (width)");
     iframe_style.height = "0";
     should_not_apply("all and (height)");
     should_not_apply("all and (width)");