Add support for BitmapShader.

This change also fixes an issue with the clip and layers.

Change-Id: I5fd9832098d8cf7ae8eb781ff9bffe7defaea279
diff --git a/libs/hwui/Snapshot.h b/libs/hwui/Snapshot.h
index 7265d91..32fee32 100644
--- a/libs/hwui/Snapshot.h
+++ b/libs/hwui/Snapshot.h
@@ -106,6 +106,18 @@
     }
 
     /**
+     * Sets the current clip.
+     */
+    void setClip(float left, float top, float right, float bottom) {
+        clipRect.set(left, top, right, bottom);
+        if (flags & kFlagDirtyTransform) {
+            flags &= ~kFlagDirtyTransform;
+            mappedClip.set(clipRect);
+            transform.mapRect(mappedClip);
+        }
+    }
+
+    /**
      * Height of the framebuffer the snapshot is rendering into.
      */
     int height;