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

Source/devtools/front_end/InspectorView.js

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 394 matching lines @@
         counterElement.id = id;
         counterElement.textContent = count;
     },
 
     /**
      * @param {number} errors
      * @param {number} warnings
      */
     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();
 
         this._createImagedCounterElementIfNeeded(errors, "error-count", "error-icon-small");
         this._createImagedCounterElementIfNeeded(warnings, "warning-count", "warning-icon-small");
 
         var errorString = errors ?  WebInspector.UIString("%d error%s", errors, errors > 1 ? "s" : "") : "";
         var warningString = warnings ?  WebInspector.UIString("%d warning%s", warnings, warnings > 1 ? "s" : "") : "";
         var commaString = errors && warnings ? ", " : "";
         this._errorWarningCountElement.title = errorString + commaString + warningString;
@@ skipping 76 matching lines @@
             window.addEventListener("scroll", this._onScrollBound, false);
         else
             window.removeEventListener("scroll", this._onScrollBound, false);
 
         WebInspector.VBox.prototype.doResize.call(this);
         this._onScroll();
     },
 
     __proto__: WebInspector.VBox.prototype
 };