DevTools: do not invalidate total layout each time console message is added.

Source/devtools/front_end/InspectorView.js

Index: Source/devtools/front_end/InspectorView.js
diff --git a/Source/devtools/front_end/InspectorView.js b/Source/devtools/front_end/InspectorView.js
index af6fd7b1b7a7aebf0065e2474e95c6f2877bfb43..b87c2c5a1f5eac780c6f23d3195b5cdd4871172f 100644
--- a/Source/devtools/front_end/InspectorView.js
+++ b/Source/devtools/front_end/InspectorView.js
@@ -412,6 +412,10 @@ WebInspector.InspectorView.prototype = {
      */
     setErrorAndWarningCounts: function(errors, warnings)
     {
+        if (this._errors === errors && this._warnings === warnings)
+            return;
+        this._errors = errors;
+        this._warnings = warnings;
         this._errorWarningCountElement.classList.toggle("hidden", !errors && !warnings);
         this._errorWarningCountElement.removeChildren();