[ash] Add TYPE_DIALOG and its item's LauncherContextMenu

ash/shelf/shelf_model.cc

Index: ash/shelf/shelf_model.cc
diff --git a/ash/shelf/shelf_model.cc b/ash/shelf/shelf_model.cc
index d5d83f12e6a1001ad4bc7ca3fc351ea965cbdf3b..8f4f10fe8b031fe0f3e60504e8dc64e05ba43de7 100644
--- a/ash/shelf/shelf_model.cc
+++ b/ash/shelf/shelf_model.cc
@@ -26,8 +26,10 @@ int LauncherItemTypeToWeight(LauncherItemType type) {
         return 1;
       case TYPE_PLATFORM_APP:
         return 2;
-      case TYPE_APP_PANEL:
+      case TYPE_DIALOG:
         return 3;
+      case TYPE_APP_PANEL:
+        return 4;
       case TYPE_UNDEFINED:
         NOTREACHED() << "LauncherItemType must be set";
         return -1;
@@ -42,8 +44,10 @@ int LauncherItemTypeToWeight(LauncherItemType type) {
         return 1;
       case TYPE_APP_LIST:
         return 2;
-      case TYPE_APP_PANEL:
+      case TYPE_DIALOG:
         return 3;
+      case TYPE_APP_PANEL:
+        return 4;
       case TYPE_UNDEFINED:
         NOTREACHED() << "LauncherItemType must be set";
         return -1;