DevTools: Implement console message logging through an extension

Source/devtools/front_end/elements/MetricsSidebarPane.js

Index: Source/devtools/front_end/elements/MetricsSidebarPane.js
diff --git a/Source/devtools/front_end/elements/MetricsSidebarPane.js b/Source/devtools/front_end/elements/MetricsSidebarPane.js
index c31a7acc50fb4633f2a72e5d6b3a051b6c4007ea..2bbdddbd74df62e84bbb87aa9237770a57cc2a69 100644
--- a/Source/devtools/front_end/elements/MetricsSidebarPane.js
+++ b/Source/devtools/front_end/elements/MetricsSidebarPane.js
@@ -433,7 +433,7 @@ WebInspector.MetricsSidebarPane.prototype = {
 
         if (computedStyle.getPropertyValue("box-sizing") === "border-box" && (styleProperty === "width" || styleProperty === "height")) {
             if (!userInput.match(/px$/)) {
-                WebInspector.console.log("For elements with box-sizing: border-box, only absolute content area dimensions can be applied", WebInspector.ConsoleMessage.MessageLevel.Error, true);
+                WebInspector.messageSink.addErrorMessage("For elements with box-sizing: border-box, only absolute content area dimensions can be applied", true);
                 return;
             }