Add support for optional titles in action modes

Optional titles will only be displayed in the CAB if they entirely fit
instead of ellipsizing.

Fixes bug 5821883

Change-Id: I0cfd6d4fd34a4fa9f520499d577706da30606811
diff --git a/core/java/com/android/internal/app/ActionBarImpl.java b/core/java/com/android/internal/app/ActionBarImpl.java
index afb5bf1..f3486bd 100644
--- a/core/java/com/android/internal/app/ActionBarImpl.java
+++ b/core/java/com/android/internal/app/ActionBarImpl.java
@@ -748,6 +748,16 @@
         }
         
         @Override
+        public void setTitleOptionalHint(boolean titleOptional) {
+            mContextView.setTitleOptional(titleOptional);
+        }
+
+        @Override
+        public boolean isTitleOptional() {
+            return mContextView.isTitleOptional();
+        }
+
+        @Override
         public View getCustomView() {
             return mCustomView != null ? mCustomView.get() : null;
         }