Reland of DevTools: require enabling CSS domain before running CSS.* commands.

third_party/WebKit/LayoutTests/css3/fonts/resources/style-matching-test.js

 function emptyFontFaceDeclarations()
 {
     var stylesheet = document.styleSheets[0];
     var rules = stylesheet.cssRules;
     var rulesLengthSnapshot = stylesheet.cssRules.length;
     if (!rulesLengthSnapshot)
         return;
     for (var i = 0; i < rulesLengthSnapshot; i++) {
         stylesheet.deleteRule(0);
     }
@@ skipping 165 matching lines @@
 
     function testNextPageElement(result)
     {
         var nextSelector = testSelectors.shift()
         if (nextSelector) {
             documentNodeSelector = "#" + nextSelector;
             platformFontsForElementWithSelector(documentNodeSelector);
         }
     }
 
-    function platformFontsForElementWithSelector(selector)
+    async function platformFontsForElementWithSelector(selector)
     {
-        InspectorTest.requestNodeId(documentNodeId, selector, onNodeId);
-
-        function onNodeId(nodeId)
-        {
-            InspectorTest.sendCommandOrDie("CSS.getPlatformFontsForNode",
-                                           { nodeId: nodeId },
-                                           onGotComputedFonts);
-        }
-
-        function onGotComputedFonts(response)
-        {
-            logResults(response);
-            nextTest();
-        }
+        var nodeId = await InspectorTest.requestNodeId(documentNodeId, selector);
+        await InspectorTest.sendCommandOrDie("CSS.enable", {});
+        var response = await InspectorTest.sendCommandOrDie("CSS.getPlatformFontsForNode",
+                                                            { nodeId: nodeId });
+        logResults(response);
+        nextTest();
     }
 
     function logResults(response)
     {
         InspectorTest.log(documentNodeSelector);
         logPassFailResult(
             documentNodeSelector,
             response.fonts[0].familyName);
     }
 
@@ skipping 63 matching lines @@
             InspectorTest.log("FAIL\n");
         } else {
             InspectorTest.log("PASS\n");
         }
     }
 };
 
 window.addEventListener("DOMContentLoaded", function () {
     runTest();
 }, false);