Split scroll factor into a 2d float.

Test: Existing unit tests, manual sanity check.
BUG=35764483

Change-Id: If6ac121452698747e1f8bc9d4ec0111bb881d4d4
(cherry picked from commit e9956c5c65ecd3aaf7390c10d135749e5adfb344)
diff --git a/api/removed.txt b/api/removed.txt
index 75da976..fa62e05 100644
--- a/api/removed.txt
+++ b/api/removed.txt
@@ -374,6 +374,10 @@
     method protected void initializeScrollbars(android.content.res.TypedArray);
   }
 
+  public class ViewConfiguration {
+    method public int getScaledScrollFactor();
+  }
+
   public static class WindowManager.LayoutParams extends android.view.ViewGroup.LayoutParams implements android.os.Parcelable {
     field public static final int TYPE_KEYGUARD = 2004; // 0x7d4
   }