Sync from upstream.

Descriptions:
==========
Add a dirty bit flag to document store to avoid checksumming during
initialization.
==========
Change the interpretation of snippet window size to be measured in unicode
characters rather than bytes.
==========
Implement snippet window shifting to more closely match the requested size.
==========
Make GetDocumentFilterData check if a document exists first, and if not, return
NOT_FOUND.
==========
Move reverse-jni-break-iterator to the tokenization/reverse_jni directory.

Bug: 185806837
Bug: 188826120
Bug: 188914218

Change-Id: I908e4b5eedc85332a318ce0e5b891a7a950720db
diff --git a/synced_AOSP_CL_number.txt b/synced_AOSP_CL_number.txt
index 4069810..35ad6d9 100644
--- a/synced_AOSP_CL_number.txt
+++ b/synced_AOSP_CL_number.txt
@@ -1 +1 @@
-set(synced_AOSP_CL_number=375495869)
+set(synced_AOSP_CL_number=378695940)