NULL previous background bitmap upon changing wallpaper

Step to reproduce it on Nexus 10 with 4.4.2(KOT49H):
1. Long press on home screen.
2. Choose wallpaper from Wallpapers.
3. Select new wallpaper and set it.
4. Repeat step 1-3 several times.
See black background instead of the wallpaper.

There are two binder objects who hold reference to the
ImageWallpaper$DrawableEngine, which keeps the big chunk
bitmap from being recycled.
One is WallpaperService$IWallpaperEngineWrapper. The client
references went away slowly, maybe several minutes after
changing wallpaper. Then the finalizer has to been executed
to GC it.
The other one is WallpaperService$Engine$BaseIWindow. Don't
know who still held reference to it even after the window
was removed.
Anyway, let the bitmap be GCed first.

Change-Id: I27f6971a3edd26472b69e59b542b27fd7c8e7b90
Signed-off-by: jshe32X<jianchunx.shen@intel.com>
Signed-off-by: Guobin Zhang <guobin.zhang@intel.com>
remove unnecessary switchUser call

If userId doesn't change, no need to do switchuser.or it will
introduce some tweak for gps modules in quick off/on because
they need cost time in off/on.

Change-Id: Ie5e408dc8be69c8a63a18bcb2cfe478cef4d70e6
Signed-off-by: Jianzheng Zhou <jianzheng.zhou@freescale.com>
Fix to memory leak leaving WallpaperCropActivity.

After running wallpaper cropper serveral times it crashes with
an OutOfMemotyException.

When leaving WallpaperCropActivity all textures are leaking until end
of process lifetime. This is due to a missing call to function
TiledImageView.destroy which in turn assures TiledImageRenderer
releases held resources.

Resolved by assuring WallpaperCropActivity calls TiledImageView.destroy
from WallpaperCropActivity.onDestroy. In case where onDestroy is not
called resources will be released anyway by process being brought down.

Change-Id: I016b1b9da5f4db8d2b14767edb59fe742415e074
Revert "Revert "services: don't clear wallpaper when SystemUI""

This reverts commit fda48b879132333c9e162e0bea1fff8068062da8.

Change-Id: I1be9fcf61699d75377828c8bdec91396307029e5
frameworks/base: Fix the random UI corruption

On low memory device, when a view goes to background. Its HW layer cache
will be destroyed to release memory. There is a very rare case that the
hardware render is not valid when destroy the layer, so the layer is not
destroyed and reused when the view comes to foreground. But the GL
context has changed, so the view is not rendered correctly due to its
HW layer cache. To fix this issue, destroy the layer in a safelyRun. Make
sure the layer is destroyed correctly.

Change-Id: I1c714e1d53db7353d5169e874a7cd0f527c3f67b
CRs-Fixed: 623239