Update to new saved pages icon.

We switched the saved pages icon on iOS to be something different, so that if
we decided to implement the watchlist in the future then we wouldn't have
issues with already using the star. This patch switches the Android icon to be
consistent with iOS.

Change-Id: I5a8ec3443eb15b1db0b42a15e9f4db5a1622355c
Merge "Update to new saved pages icon."