wallpapercropper: OOM issue while opening *.bmp image

This change manages setting of large images as
wallpapers without encountering OOM.

CRs-fixed: 619815
Change-Id: Id6f75d961c53fb5858b9bea542bf48ec6e048e2b
WallpaperCropper: Fix crash when set .gif as wallpaper

It returns an equivalent scaled cropBounds as true
crop bounds, then it set the rounded rect by rounding
"out" the true crop rect, this make the rounded crop
rect may out range of the original bitmap, then an error
will happen.

We change to check the rounded crop rect, if it is out
the range of original bitmap, we set the original bitmap
bounds as rounded crop bounds.

CRs-Fixed: 622582

Change-Id: I215ef2a0165adaaadb05c62dee741a8ea6926144