Bug 1362103 - Suppress animation on first window opening. r=florian

Enabled by default behind the browser.suppress_first_window_animation pref.

MozReview-Commit-ID: 4mzy4Qif0LX

--HG--
extra : rebase_source : 926dd03514dd1792ee1c9d9a662a4a3657bc6796

browser/app/profile/firefox.js

@@ -1651,3 +1651,5 @@ pref("browser.sessionstore.restore_tabs_lazily", true);
 pref("urlclassifier.malwareTable", "goog-malware-shavar,goog-unwanted-shavar,goog-malware-proto,goog-unwanted-proto,test-malware-simple,test-unwanted-simple");
 pref("urlclassifier.phishTable", "goog-phish-shavar,goog-phish-proto,test-phish-simple");
 #endif
+
+pref("browser.suppress_first_window_animation", true);

browser/components/nsBrowserContentHandler.js

@@ -576,7 +576,12 @@ nsBrowserContentHandler.prototype = {
       // The global PB Service consumes this flag, so only eat it in per-window
       // PB builds.
       if (PrivateBrowsingUtils.isInTemporaryAutoStartMode) {
-        this.mFeatures = ",private";
+        this.mFeatures += ",private";
+      }
+
+      if (Services.prefs.getBoolPref("browser.suppress_first_window_animation") &&
+          !Services.wm.getMostRecentWindow("navigator:browser")) {
+        this.mFeatures += ",suppressanimation";
       }
     }