[ActivityManager] Ensure alive process is not killedByAm.

Symptom: Unable to kill by Am again and will be skipped updating its oom adj.

Root Cause:
A restarted process will reuse original process record.
The flag killedByAm will keep previous state.

Solution:
Reset the flag killedByAm to false when the process is started.

Note: Found another similiar patch If95137d91939cc44882ad2813131bcde0edd0c1b

Change-Id: I59a86648ca8d0aed4c489d92751af120aae5ef90
[ActivityManager] Prevent kill a restarted process again.

Root Cause:
Use removeTask with flag ActivityManager.REMOVE_TASK_KILL_PROCESS will set waitingToKill = "remove task"
to the target process when its setSchedGroup is not BG_NONINTERACTIVE.
Later the target process may be killed when applying oom-adj due to setSchedGroup has changed to BG_NONINTERACTIVE.
If the process is needed to restart, the process record will be resued.
Then the restarted process may be killed again because its waitingToKill is not null.

Solution:
Clean waitingToKill when process is dead.

Change-Id: I5ffb5388127f4221da4c700d3f1c224f7ca6e7b2
[ActivityManager] Avoid keeping restarting home when only home activity exists.

Root Cause:
When there is only home activity existed,
updating home apk will call forceStopPackageLocked to finish the activity.
Then activity history becomes empty, then home will be launched,
but its package is still target to close that results a loop.

Solution:
If home activity has been force-stopped, do not stop the same home activity again.

Change-Id: Icff12028d407873c2e6f50a06bcad231b908ccbd
[ActivityManager] Prevent potential deadlock from system error dialog and InputMethodManager.

Sympton:
When application crash in a special timing and system server's InputMethodManager is binding, deadlock may occur.

Root Cause:
Thread(1): When using InputMethodManager in system server, it will lock mH(handler) of InputMethodManager,
and sometimes it will call to InputMethodManagerService::showCurrentInputLocked and will call bindService at some condition,
then it will also lock ActivityManagerService.
Thread(2): When an application crashed, it will lock ActivityManager when showing crash dialog, inside the dialog,
it will call setEnabled of Button and lock mH of InputMethodManager.setEnable of TextView will lock IMM's handler.
So the deadlock happened as the flow: (2) lock AMS -> (1)lock mH -> (2)wait mH -> (1) wait AMS

Solution:
Reduce nested lock of error dialog: post message to let (2) lock mH after release AMS lock.

Change-Id: Id85c29406236db3b5fca9655fde1fcaf0afd1337
[ActivityManager] Move top task to top in window manager

Symptom:
In certain situations, application starts activity while
it is in background. When an existing background activity
starts a new activity which results to be kept in the same
background task, the new activity won't be resumed.
In that case, the background task (sourceTask) should not be
moved to top in window manager.

Solution:
Move top task of the target stack to top in window manager

Change-Id: Id7a37ea67ce1f80e0c2b5399865c51fd7113deb8
[ActivityManager] Do not finish root activity when reset task

Symptom:
The root activity not always located at index 0 of the task.
For example, the index 1 activity will become the new root
when the original root activity (at index 0) finished.
The new root activity might be finished unexpectedly before
the original root activity actually destroyed.

Solution:
Check frontOfTask to avoid finishing the root activity unexpectedly

Change-Id: I623ab97e9c95c83b3cfe7c9dfc151a291a391ea4
[ActivityManager]: Update home process when home activity resumed

Symptom:
  When switch between two home activities, the home process might not be updated to the correct one. In that case, the home activity might be killed easily.

Root Cause:
  The home process is updated only when a home activity is newly created or being restarted. ActivityManager did not update the home process when simply resume a home activity.

Solution:
  Update home process when home activity resumed

Reproduce Steps:
  1. Install a launcher application, such as Apex Launcher
  2. Press home key to change to Apex Launcher by "Just once" option
  3. Press home key to switch back to original home activity by "Just once" option.
     (The home process is still the Apex Launcher's process because ActivityManager does not update the home process when resuming the original home activity.)

Change-Id: I046279ca7ba851a283ee67ea19202890f7b3f343
[ActivityManager] Avoid mistaking visibility by finishing task.

Sympton:
Next activity only adds to history but does not launch/resume then results ANR.

Root Cause:
In a rare timing, some windows are switched at the same time,
it will cause some finishing records on the top temporarily,
then set startIt to false that skip to resume the real top activty.

Solution:
If all activities in a task are finishing, do not use it to check.
The behavior/checking is the same concept as in JellyBean:
            // If starting in an existing task, find where that is...
            boolean startIt = true;
            for (int i = NH-1; i >= 0; i--) {
                ActivityRecord p = mHistory.get(i);
                if (p.finishing) { // <--
                    continue;
                }

Change-Id: I9d81a7b5182400c52e173da23eee61c74692beee
[ActivityManager] Prevent coredump file may not complete for testing.

Sympton:
During testing, skip kill native crash process manually because it will continue to die by default.

Root Cause:
Large process may take some time to do coredump.In auto test, crash process will be killed immediately that results incomplete coredump file.

Solution:
If the tester (IActivityController) will handle app crash event,
Do not kill native crashed process if the rom is debuggable.

Change-Id: Ia360af147d694125d440e5ba2f958c4759a50494
Fix a bug that the RecentTask list of other’s may show up to non-primary users.

When switching to a newly created user, the user may face this bug when he opens the RecentTask screen.
A possible bug scenario is described as follows:
A user id of a removed user may be recycled when created a new user.
However, mRecentTasks is not correctly controlled so that old information may still remain and be possibly mapped to wrong user.
This patch prevents this bug by explicitly removing old information in mRecentTasks when removing existing user.

Change-Id: I1874dbd604598a5d740ae1e034981e21214c15c6
Signed-off-by: Eunae Kim <eunae.kim@lge.com>