Attempt to fix presubmit failure

System crashed while running presubmit. The #getDisplayIdsLocked()
was not guarded by synchronization since commit 05e1c1a.

Bug: 170451499
Test: presubmit
Change-Id: I4f2dfd2637632f722d6223469d478940db152e45

1 files changed, 3 insertions, 1 deletions

diff --git a/services/core/java/com/android/server/display/DisplayManagerService.java b/services/core/java/com/android/server/display/DisplayManagerService.java
index af62aeba4cfb..ca94efc3e5a0 100644
--- a/services/core/java/com/android/server/display/DisplayManagerService.java
+++ b/services/core/java/com/android/server/display/DisplayManagerService.java
@@ -1768,7 +1768,9 @@ public final class DisplayManagerService extends SystemService {
             final int callingUid = Binder.getCallingUid();
             final long token = Binder.clearCallingIdentity();
             try {
-                return mLogicalDisplayMapper.getDisplayIdsLocked(callingUid);
+                synchronized (mSyncRoot) {
+                    return mLogicalDisplayMapper.getDisplayIdsLocked(callingUid);
+                }
             } finally {
                 Binder.restoreCallingIdentity(token);
             }