Add autotest private API to wait for orientation change.

Bug: 1007397
Test: covered by unittest
Change-Id: Ib6b5ed47c3368133d0dcccf7a9be202570d0f541
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1833007
Commit-Queue: Mitsuru Oshima <[email protected]>
Reviewed-by: Ben Wells <[email protected]>
Cr-Commit-Position: refs/heads/master@{#702888}
diff --git a/extensions/browser/extension_function_histogram_value.h b/extensions/browser/extension_function_histogram_value.h
index 942411e0..6eadf4cf 100644
--- a/extensions/browser/extension_function_histogram_value.h
+++ b/extensions/browser/extension_function_histogram_value.h
@@ -1451,6 +1451,7 @@
   AUTOTESTPRIVATE_GETCLIPBOARDTEXTDATA = 1388,
   AUTOTESTPRIVATE_SETCLIPBOARDTEXTDATA = 1389,
   AUTOTESTPRIVATE_INITIALIZEEVENTS = 1390,
+  AUTOTESTPRIVATE_WAITFORDISPLAYROTATION = 1391,
   // Last entry: Add new entries above, then run:
   // python tools/metrics/histograms/update_extension_histograms.py
   ENUM_BOUNDARY