Fix GpsLocationProvider wake lock book keeping.

The GpsLocationProvider typically acquires a wake lock
before sending a message to its handler then releases it
after the message has been handled.

There were two cases where messages might be removed from
the handler, resulting in the wake lock being released.

There were also two cases where background tasks were being
started while not holding a wake lock for the duration.

Fixed these issues and marked the GpsLocationProvider handler
as asynchronous too so that it doesn't accidentally get
blocked by traversals if it happens to share a thread with some UI.

Bug: 7057752
Change-Id: I8e12fc91ae943e84db068c08ec809879537503c6

Author: Jeff Brown

services/java/com/android/server/location/GpsLocationProvider.java

@@ -598,6 +598,8 @@ private void handleInjectNtpTime() {
         }
         mInjectNtpTimePending = STATE_DOWNLOADING;
 
+        // hold wake lock while task runs
+        mWakeLock.acquire();
         AsyncTask.THREAD_POOL_EXECUTOR.execute(new Runnable() {
             @Override
             public void run() {
@@ -628,14 +630,16 @@ public void run() {
                     delay = RETRY_INTERVAL;
                 }
 
-                mHandler.sendMessage(Message.obtain(mHandler, INJECT_NTP_TIME_FINISHED));
+                sendMessage(INJECT_NTP_TIME_FINISHED, 0, null);
 
                 if (mPeriodicTimeInjection) {
                     // send delayed message for next NTP injection
                     // since this is delayed and not urgent we do not hold a wake lock here
-                    mHandler.removeMessages(INJECT_NTP_TIME);
-                    mHandler.sendMessageDelayed(Message.obtain(mHandler, INJECT_NTP_TIME), delay);
+                    mHandler.sendEmptyMessageDelayed(INJECT_NTP_TIME, delay);
                 }
+
+                // release wake lock held by task
+                mWakeLock.release();
             }
         });
     }
@@ -652,6 +656,8 @@ private void handleDownloadXtraData() {
         }
         mDownloadXtraDataPending = STATE_DOWNLOADING;
 
+        // hold wake lock while task runs
+        mWakeLock.acquire();
         AsyncTask.THREAD_POOL_EXECUTOR.execute(new Runnable() {
             @Override
             public void run() {
@@ -664,17 +670,17 @@ public void run() {
                     native_inject_xtra_data(data, data.length);
                 }
 
-                mHandler.sendMessage(Message.obtain(mHandler, DOWNLOAD_XTRA_DATA_FINISHED));
+                sendMessage(DOWNLOAD_XTRA_DATA_FINISHED, 0, null);
 
                 if (data == null) {
                     // try again later
                     // since this is delayed and not urgent we do not hold a wake lock here
-                    mHandler.removeMessages(DOWNLOAD_XTRA_DATA);
-                    mHandler.sendMessageDelayed(Message.obtain(mHandler, DOWNLOAD_XTRA_DATA),
-                            RETRY_INTERVAL);
+                    mHandler.sendEmptyMessageDelayed(DOWNLOAD_XTRA_DATA, RETRY_INTERVAL);
                 }
-            }
 
+                // release wake lock held by task
+                mWakeLock.release();
+            }
         });
     }
 
@@ -1475,11 +1481,17 @@ private void requestRefLocation(int flags) {
 
     private void sendMessage(int message, int arg, Object obj) {
         // hold a wake lock until this message is delivered
+        // note that this assumes the message will not be removed from the queue before
+        // it is handled (otherwise the wake lock would be leaked).
         mWakeLock.acquire();
         mHandler.obtainMessage(message, arg, 1, obj).sendToTarget();
     }
 
     private final class ProviderHandler extends Handler {
+        public ProviderHandler() {
+            super(true /*async*/);
+        }
+
         @Override
         public void handleMessage(Message msg) {
             int message = msg.what;