Remove dependence on SK_LEGACY_PICTURE_DRAW_API.

Call SkPicture::playback() instead of ::draw().

Also, no need longer need the const_cast.

Change-Id: I4742d2fd5c5b918db492ec2ef6a84ea7d6151cdd

core/jni/android/graphics/Picture.cpp

@@ -106,8 +106,7 @@ void Picture::draw(Canvas* canvas) {
         SkASSERT(NULL != mPicture.get());
     }
     if (NULL != mPicture.get()) {
-        // TODO: remove this const_cast once pictures are immutable
-        const_cast<SkPicture*>(mPicture.get())->draw(canvas->getSkCanvas());
+        mPicture.get()->playback(canvas->getSkCanvas());
     }
 }