Add the missing overriden API

This is exposed by the CTS test.

Change-Id: Ic25fda1567d8c8504612d4e825dbb646f7db1076
diff --git a/graphics/java/android/graphics/drawable/AnimatedVectorDrawable.java b/graphics/java/android/graphics/drawable/AnimatedVectorDrawable.java
index d325bd0..ab0b7a5 100644
--- a/graphics/java/android/graphics/drawable/AnimatedVectorDrawable.java
+++ b/graphics/java/android/graphics/drawable/AnimatedVectorDrawable.java
@@ -259,6 +259,13 @@
         return mAnimatedVectorState.mVectorDrawable.setLayoutDirection(layoutDirection);
     }
 
+    /**
+     * AnimatedVectorDrawable is running on render thread now. Therefore, if the root alpha is being
+     * animated, then the root alpha value we get from this call could be out of sync with alpha
+     * value used in the render thread. Otherwise, the root alpha should be always the same value.
+     *
+     * @return the containing vector drawable's root alpha value.
+     */
     @Override
     public int getAlpha() {
         return mAnimatedVectorState.mVectorDrawable.getAlpha();
@@ -275,6 +282,11 @@
     }
 
     @Override
+    public ColorFilter getColorFilter() {
+        return mAnimatedVectorState.mVectorDrawable.getColorFilter();
+    }
+
+    @Override
     public void setTintList(ColorStateList tint) {
         mAnimatedVectorState.mVectorDrawable.setTintList(tint);
     }