Sync from upstream.

Descriptions:

============
Make IcingSearchEngine to be non-Final so that it can be mocked
in AppSearch

Change-Id: I004fe8556c379e7041c1390ffe08a7539b4e25a3
diff --git a/java/src/com/google/android/icing/IcingSearchEngine.java b/java/src/com/google/android/icing/IcingSearchEngine.java
index 3d25908..1f5fb51 100644
--- a/java/src/com/google/android/icing/IcingSearchEngine.java
+++ b/java/src/com/google/android/icing/IcingSearchEngine.java
@@ -53,9 +53,11 @@
  *
  * <p>If this instance has been closed, the instance is no longer usable.
  *
+ * <p>Keep this class to be non-Final so that it can be mocked in AppSearch.
+ *
  * <p>NOTE: This class is NOT thread-safe.
  */
-public final class IcingSearchEngine implements Closeable {
+public class IcingSearchEngine implements Closeable {
 
   private static final String TAG = "IcingSearchEngine";
   private static final ExtensionRegistryLite EXTENSION_REGISTRY_LITE =
diff --git a/synced_AOSP_CL_number.txt b/synced_AOSP_CL_number.txt
index e2be49a..a7d657e 100644
--- a/synced_AOSP_CL_number.txt
+++ b/synced_AOSP_CL_number.txt
@@ -1 +1 @@
-set(synced_AOSP_CL_number=368346709)
+set(synced_AOSP_CL_number=368957181)