Added webstorePrivate API functions for launching ephemeral apps

Implements:
- webstorePrivate.launchEphemeralApp()
- webstorePrivate.getEphemeralAppsEnabled()

BUG=380980
TEST=browser_tests (EphemeralAppWebstorePrivateApiTest*)

Review URL: https://codereview.chromium.org/342433003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@278945 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/extensions/browser/extension_function_histogram_value.h b/extensions/browser/extension_function_histogram_value.h
index 163dc8b..7d0263a5 100644
--- a/extensions/browser/extension_function_histogram_value.h
+++ b/extensions/browser/extension_function_histogram_value.h
@@ -853,6 +853,8 @@
   VIRTUALKEYBOARDPRIVATE_OPENSETTINGS,
   BLUETOOTHLOWENERGY_CONNECT,
   BLUETOOTHLOWENERGY_DISCONNECT,
+  WEBSTOREPRIVATE_GETEPHEMERALAPPSENABLED,
+  WEBSTOREPRIVATE_LAUNCHEPHEMERALAPP,
   // Last entry: Add new entries above and ensure to update
   // tools/metrics/histograms/histograms/histograms.xml.
   ENUM_BOUNDARY