DevTools: [CSS] remove getAllStylesheets method from protocol

LayoutTests/inspector/styles/styles-test.js

+function initialize_StylesTests()
+{
+
+InspectorTest.waitForStylesheetsOnFrontend = function(styleSheetsCount, callback)
+{
+    function styleSheetComparator(a, b)
+    {
+        if (a.sourceURL < b.sourceURL)
+            return -1;
+        else if (a.sourceURL > b.sourceURL)
+            return 1;
+        return a.startLine - b.startLine || a.startColumn - b.startColumn;
+    }
+
+    var styleSheets = WebInspector.cssModel.allStyleSheets();
+    if (styleSheets.length >= styleSheetsCount) {
+        styleSheets.sort(styleSheetComparator);
+        callback(styleSheets);
+        return;
+    }
+
+    function onStyleSheetAdded()
+    {
+        var styleSheets = WebInspector.cssModel.allStyleSheets();
+        if (styleSheets.length < styleSheetsCount)
+            return;
+
+        WebInspector.cssModel.removeEventListener(WebInspector.CSSStyleModel.Events.StyleSheetAdded, onStyleSheetAdded, this);
+        styleSheets.sort(styleSheetComparator);
+        callback(null, styleSheets);
+    }
+
+    WebInspector.cssModel.addEventListener(WebInspector.CSSStyleModel.Events.StyleSheetAdded, onStyleSheetAdded, this);
+}
+
+}