setKeyboardState API

Allows javascript to trigger instantiation of the virtual keyboard.

BUG=522203

Review URL: https://codereview.chromium.org/1289813008

Cr-Commit-Position: refs/heads/master@{#345083}
diff --git a/extensions/browser/extension_function_histogram_value.h b/extensions/browser/extension_function_histogram_value.h
index e329a77..1c856aa4 100644
--- a/extensions/browser/extension_function_histogram_value.h
+++ b/extensions/browser/extension_function_histogram_value.h
@@ -1136,6 +1136,7 @@
   CASTDEVICESPRIVATE_UPDATEDEVICES,
   SYSTEM_DISPLAY_ENABLEUNIFIEDDESKTOP,
   BROWSINGDATA_REMOVECACHESTORAGE,
+  VIRTUALKEYBOARDPRIVATE_SETKEYBOARDSTATE,
   // Last entry: Add new entries above, then run:
   // python tools/metrics/histograms/update_extension_histograms.py
   ENUM_BOUNDARY