Bug 1414403 - Display screenshot help message on all platforms. r=mossop

MozReview-Commit-ID: JSxTrXt9tnL

--HG--
extra : rebase_source : 8878b12da8a8612e59c6e760a103d402108ea4e5

browser/components/nsBrowserContentHandler.js

@@ -468,10 +468,8 @@ nsBrowserContentHandler.prototype = {
     } else {
       info += "  --preferences      Open Preferences dialog.\n";
     }
-    if (AppConstants.platform == "win" || AppConstants.MOZ_WIDGET_GTK) {
-      info += "  --screenshot [<path>] Save screenshot to <path> or in working directory.\n";
-      info += "  --window-size width[,height] Width and optionally height of screenshot.\n";
-    }
+    info += "  --screenshot [<path>] Save screenshot to <path> or in working directory.\n";
+    info += "  --window-size width[,height] Width and optionally height of screenshot.\n";
     info += "  --search <term>    Search <term> with your default search engine.\n";
     return info;
   },