themechooser: decode inSampleSize prior to load wallpaper bitmap

Decode inSampleSize to avoid OOM exceptions loading the wallpaper bitmaps

JIRA: CYAN-4795
https://jira.cyanogenmod.org/browse/CYAN-4795
Signed-off-by: Jorge Ruesga <jorge@ruesga.com>

Change-Id: I2cbc809d5fe6b119f0715db40d2f175a05c9b913
Use getThemedResourcesForApplication for icons

Since we no longer pass bitmaps around in ComposedIconInfo we need
to make sure the icons are actually attached to the resources in
order to retrieve the drawables for the composed icons.

Change-Id: I52cda714d54ce1c8b06dff1376c2ca117d4c443a