Bug 747228 - [layout view] We should not use the animation when the layout view is opened on a non-user action. r=dcamp

browser/base/content/highlighter.css

@@ -111,12 +111,15 @@ html|*#highlighter-nodeinfobar-tagname {
 }
 
 #inspector-layoutview-container > iframe {
-  -moz-transition-property: height;
-  -moz-transition-duration: 0.1s;
   /* header size */
   height: 22px;
 }
 
+#inspector-layoutview-container:not([disable-transitions]) > iframe {
+  -moz-transition-property: height;
+  -moz-transition-duration: 0.2s;
+}
+
 #inspector-layoutview-container > iframe[open] {
   /* header size + layout view size: 22px + 155px */
   height: 177px;

browser/devtools/layoutview/LayoutView.jsm

@@ -254,6 +254,9 @@ LayoutView.prototype = {
     if (aUserAction) {
       this.inspector._layoutViewIsOpen = true;
       Services.prefs.setBoolPref("devtools.layoutview.open", true);
+      this.view.removeAttribute("disable-transitions");
+    } else {
+      this.view.setAttribute("disable-transitions", "true");
     }
     this.iframe.setAttribute("open", "true");
     this.update();
@@ -272,6 +275,9 @@ LayoutView.prototype = {
     if (aUserAction) {
       this.inspector._layoutViewIsOpen = false;
       Services.prefs.setBoolPref("devtools.layoutview.open", false);
+      this.view.removeAttribute("disable-transitions");
+    } else {
+      this.view.setAttribute("disable-transitions", "true");
     }
     this.iframe.removeAttribute("open");
   },