DevTools: [CSS] introduce strong types

LayoutTests/inspector/elements/styles-1/add-new-rule-inline-style-csp.html

Index: LayoutTests/inspector/elements/styles-1/add-new-rule-inline-style-csp.html
diff --git a/LayoutTests/inspector/elements/styles-1/add-new-rule-inline-style-csp.html b/LayoutTests/inspector/elements/styles-1/add-new-rule-inline-style-csp.html
index 9ae897950ae5117947b0525e22fb595304c56e6a..f339bd4428213f0bd3ee690b564ad2fc47a9c6ac 100644
--- a/LayoutTests/inspector/elements/styles-1/add-new-rule-inline-style-csp.html
+++ b/LayoutTests/inspector/elements/styles-1/add-new-rule-inline-style-csp.html
@@ -73,13 +73,13 @@ function test()
         {
             InspectorTest.cssModel.getInlineStylesAsync(nodeId, stylesCallback);
 
-            function stylesCallback(inlineStyle)
+            function stylesCallback(inlineStyleResult)
             {
-                if (!inlineStyle) {
+                if (!inlineStyleResult || !inlineStyleResult.inlineStyle) {
                     InspectorTest.completeTest();
                     return;
                 }
-                inlineStyle.appendProperty("font-size", "14px", appendCallback);
+                inlineStyleResult.inlineStyle.appendProperty("font-size", "14px", appendCallback);
             }
 
             function appendCallback(newStyle)