DocumentsUI: Add a standalone File Manager

This commit adds a standalone mode to the DocumentsUI, to let
it act as a file manager/explorer.
You can browse your storage contents, open files, and delete them,
as well as do everything that the DocumentsUI can do (ie. sort
by name/size/type, list and grid view, recents, search, ...).

This gives us a consistent file browsing UX accross all apps
that uses the new documents API.

Change-Id: If73a3c100f010bdb766c843976d4fd3573ea805c
Conflicts:
	packages/DocumentsUI/res/drawable-xxhdpi/ic_filemanager.png
DocumentsUI: Allow open files instead of URIs

Check files' real path and mime type to open them only in standalone mode.
This allows, for example, installing apks.

Change-Id: I4501c694db84b8595cd3928752254a8914539972
Fix very long app_name crash.

http://ibrahimbalic.com/2014/android-os-memory-corruption-bug/ found an stack overflow bug.
The very long app_name make libandroid_runtime allocate a very large array on stack, the stack may overflow to other data areas in this situation.
This patch allocate large array on heap instead of on stack to avoid segment fault when doing memcpy.

Change-Id: I99999569b852d43a9c7a6eb1fa80e9f1a1f4e2b2
fix WRITE_SETTINGS to be "dangerous"

(see http://www.fireeye.com/blog/technical/2014/04/occupy_your_icons_silently_on_android.html for an explanation why this is dangerous)

Change-Id: I8f938dc4f528aa2ccbca3d4cec235feb0299c0bd
Fix setSurfaceTexture to handle surface caching

Changed the TextureView.setSurfaceTexture to apply the
existing listener to the surface provided in the method.
This is done to allow surface caching to work.
Whenever a new SurfaceTexture gets created, its listener is
created as well, so when the setSurfaceTexture is called
we should be attaching the listener to the new surface.

Change-Id: I4c1a704c587e977ab7a6b1fe3a7d3e0d20d00218
CRs-Fixed: 639136