Allow apps to bypass Power Save restrictions when launched from a Notification's PendingIntent.

This scenario typically happens when the device is on Doze Mode and a
notification action is triggered from a Wear device.

In a nutshell, the workflow is:

- ProcessRecord has a flag telling whether a process has "whitelist
  management" privileges.
- When NotificationManager binds a new NotificationListenerService, it
  sets the BIND_ALLOW_WHITELIST_MANAGEMENT flag.
- On bind(), ActiveService asserts that only system apps can set that
  flag.
- On computeOomAdjLocked(), ActivityManagerService sets the
  ProcessRecord flag if necessary.
- Upon creating a notification, NotificationManager calls AM to mark its
  PendingIntents as coming from a notification.
- When PendingIntentRecord sends it to the target, it checks if it's
  from a notification and if so calls AM to do the temp whitelist.
- On unbind(), ActiveService removes the ProcessRecord flag if necessary.

Fixes: 28818704

Change-Id: I00d46036a2cbb73f7f733fd35bf0b743a02807a1
diff --git a/services/core/java/com/android/server/am/ProcessRecord.java b/services/core/java/com/android/server/am/ProcessRecord.java
index da18f32..691fd2a 100644
--- a/services/core/java/com/android/server/am/ProcessRecord.java
+++ b/services/core/java/com/android/server/am/ProcessRecord.java
@@ -194,6 +194,8 @@
 
     // Process is currently hosting a backup agent for backup or restore
     public boolean inFullBackup;
+    // App is allowed to manage whitelists such as temporary Power Save mode whitelist.
+    boolean whitelistManager;
 
     void dump(PrintWriter pw, String prefix) {
         final long now = SystemClock.uptimeMillis();
@@ -376,6 +378,9 @@
                     }
                     pw.println();
         }
+        if (whitelistManager) {
+            pw.print(prefix); pw.print("whitelistManager="); pw.println(whitelistManager);
+        }
         if (activities.size() > 0) {
             pw.print(prefix); pw.println("Activities:");
             for (int i=0; i<activities.size(); i++) {