resolve merge conflicts of 27ddeff723 to master.

Change-Id: I6dad081fc6dfafb78d5bd73d84e184bae7f6fd1b

packages/DocumentsUI/src/com/android/documentsui/RecentLoader.java

@@ -36,7 +36,7 @@ import android.text.format.DateUtils;
 import android.util.Log;
 
 import com.android.documentsui.model.RootInfo;
-
+import com.android.internal.annotations.GuardedBy;
 import com.google.common.util.concurrent.AbstractFuture;
 
 import libcore.io.IoUtils;
@@ -79,6 +79,7 @@ public class RecentLoader extends AsyncTaskLoader<DirectoryResult> {
     private final RootsCache mRoots;
     private final State mState;
 
+    @GuardedBy("mTasks")
     private final HashMap<RootInfo, RecentTask> mTasks = new HashMap<>();
 
     private final int mSortOrder = State.SORT_ORDER_LAST_MODIFIED;
@@ -165,6 +166,12 @@ public class RecentLoader extends AsyncTaskLoader<DirectoryResult> {
 
     @Override
     public DirectoryResult loadInBackground() {
+        synchronized (mTasks) {
+            return loadInBackgroundLocked();
+        }
+    }
+
+    private DirectoryResult loadInBackgroundLocked() {
         if (mFirstPassLatch == null) {
             // First time through we kick off all the recent tasks, and wait
             // around to see if everyone finishes quickly.
@@ -302,8 +309,10 @@ public class RecentLoader extends AsyncTaskLoader<DirectoryResult> {
         // Ensure the loader is stopped
         onStopLoading();
 
-        for (RecentTask task : mTasks.values()) {
-            IoUtils.closeQuietly(task);
+        synchronized (mTasks) {
+            for (RecentTask task : mTasks.values()) {
+                IoUtils.closeQuietly(task);
+            }
         }
 
         IoUtils.closeQuietly(mResult);