Fix Watchdog HeartbeatHandler to run on correct thread

The HeartbeatHandler for the System Server Watchdog has been running
on the wrong thread due to a race condition in initialization.  It's
designed to run on ServerThread, so that it can catch lockups in the
main looper of the System Server.  It has been running on
ActivityManagerThread instead, so it does not detect lockups on the
ServerThread as it should.

ActivityManagerService is calling Watchdog.getInstance() before
ServerThread calls Watchdog.getInstance().init(), so the handler is
being bound to the ActivityManagerThread instead of the ServerThread.

Explicitly bind HeartbeatHandler to ServerThread, so that the Watchdog
catches lockups on this critical thread.

Change-Id: Iccb184ac3adb817feb86ed4ee0e50e443bf74636
Remove the fixed-length buffer in DdmHandleNativeHeap.getLeakInfo.

It was possible to overrun this buffer, and even if you did fill
the buffer in a single read and exit the loop, the "string" still
wouldn't be terminated.

Bug: 8468088
Change-Id: Ia19f4d26dfd79e7b63807a7ec9540b932163d246
Two REMOVE_PROVIDER messages caused by race condition.

Fix a bug in unstable ContentProvider.
IllegalStateException: ref counts can't go to zero here: stable=0 unstable=0
IllegalStateException: unstable count < 0: -1

There is a race between main thread and background database thread. Main thread
is responsible for handling the REMOVE_PROVIDER message. Database thread starts
insert or query request again and again. acquireProvider in db thread will often
snatch provider from the jaws of death, sometime it fails to remove REMOVE_PROVIDER
which is already fired out from MessageQueue. But completeRemoveProvider in main
thread gets suspended when trying to execute the critical section. If db thread
released the provider before main thread resumes the execution, then two
REMOVE_PROVIDER messages will be executed.

Change-Id: I8588aa1d1a8bc444dcd2adf6f8bc3f055cebbdc4
Signed-off-by: Guobin Zhang <guobin.zhang@intel.com>
Clarify the documentation of SparseArray.indexOfValue.

Bug: https://code.google.com/p/android/issues/detail?id=53297
Change-Id: I28725a2d03d4c11948bfe4fb90d730c86bf41481