Added missing permission declaration on <service> tag of AccessibilityService guide documentation (Building Accessibility Services)

With code snippet on current docs, the accessibility service does not show up on the Settings > Accessibility > Services list, with API level 17 or higher. In order to declare service correctly, user have to declare "permission" property with value of "android.permission.BIND_ACCESSIBILITY_SERVICE".

Change-Id: I70c8f98d4ff6fd2286bf5866098b22443afb6cd9
more locale-appropriate screenshot share text

The SimpleDateFormat version of this produces very poor results in
locales other than en_US. Trusting DateFormat to do its thing
produces more consistently-pleasing results across all locales.

(cherry-pick of e45e1f2efe69ba931efa88c6e33879fbc8d8c4c1.)

Change-Id: I7f1714446bb50285d851e8e313e7f32a0a822bf2
Reduce EntropyMixer seed size from 4096 to 512 bytes.

The suggested seed size from Linux drivers/char/random.c is 512 bytes
rather than the 4096 bytes currently used.

Change-Id: I3dd55105f0a95ce9cda34b4cf08987b8a28c4ac9
Make EntropyMixer mix in output of Hardware RNG into Linux RNG.

On devices with Hardware RNG (HW RNG), this makes EntropyMixer
periodically (every three hours) read 512 bytes from HW RNG and mix
them into the Linux RNG.

This is done without increasing Linux RNG's entropy estimates to
avoid having to trust the quality of the HW RNG. This approach cannot
reduce the quality of the Linux RNG output, but may increase it.

Change-Id: Ifde851004301ffd41b2189151a64a0c5989c630f
framework/base: Handle ASSOC-REJECT events

Disable current network and enable other saved networks(if any)
once number of ASSOC-REJECTs on an attempt to connect to a corresponding
network exceeds the threshold.

Change-Id: Iac3c1596aa800d93c55b0ac5d8070a058c3842bd