Fix bug 5258435 - ActionBar.setBackgroundDrawable

Fix this call to work properly and add methods for setting
split/stacked bar backgrounds to match existing styleable elements.

Change-Id: I8c6b1c598af1110f84a9098683d8e0226daf2e27
diff --git a/core/java/com/android/internal/app/ActionBarImpl.java b/core/java/com/android/internal/app/ActionBarImpl.java
index 90d19fd..ccca22e 100644
--- a/core/java/com/android/internal/app/ActionBarImpl.java
+++ b/core/java/com/android/internal/app/ActionBarImpl.java
@@ -346,7 +346,17 @@
     }
 
     public void setBackgroundDrawable(Drawable d) {
-        mContainerView.setBackgroundDrawable(d);
+        mContainerView.setPrimaryBackground(d);
+    }
+
+    public void setStackedBackgroundDrawable(Drawable d) {
+        mContainerView.setStackedBackground(d);
+    }
+
+    public void setSplitBackgroundDrawable(Drawable d) {
+        if (mSplitView != null) {
+            mSplitView.setSplitBackground(d);
+        }
     }
 
     public View getCustomView() {