Throw exception when setting a fg/bg on TextureView

Change-Id: Iead53e0947d941ebc1331f77fc478c475e24c812
diff --git a/core/java/android/view/TextureView.java b/core/java/android/view/TextureView.java
index cdc196e..197ea09 100644
--- a/core/java/android/view/TextureView.java
+++ b/core/java/android/view/TextureView.java
@@ -23,6 +23,7 @@
 import android.graphics.Paint;
 import android.graphics.Rect;
 import android.graphics.SurfaceTexture;
+import android.graphics.drawable.Drawable;
 import android.util.AttributeSet;
 import android.util.Log;
 
@@ -294,6 +295,22 @@
     public void buildLayer() {
     }
 
+    @Override
+    public void setForeground(Drawable foreground) {
+        if (foreground != null) {
+            throw new UnsupportedOperationException(
+                    "TextureView doesn't support displaying a foreground drawable");
+        }
+    }
+
+    @Override
+    public void setBackgroundDrawable(Drawable background) {
+        if (background != null) {
+            throw new UnsupportedOperationException(
+                    "TextureView doesn't support displaying a background drawable");
+        }
+    }
+
     /**
      * Subclasses of TextureView cannot do their own rendering
      * with the {@link Canvas} object.