Add chrome.webcamPrivate idl

This also adds the stubs for all the functions.

BUG=346492

Review URL: https://codereview.chromium.org/205243005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@263287 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/extensions/browser/extension_function_histogram_value.h b/extensions/browser/extension_function_histogram_value.h
index 8a4f621e5..7397ef1 100644
--- a/extensions/browser/extension_function_histogram_value.h
+++ b/extensions/browser/extension_function_histogram_value.h
@@ -778,6 +778,9 @@
   FILESYSTEMPROVIDERINTERNAL_UNMOUNTREQUESTEDSUCCESS,
   FILESYSTEMPROVIDERINTERNAL_UNMOUNTREQUESTEDERROR,
   MEDIAGALLERIES_DROPPERMISSIONFORMEDIAFILESYSTEM,
+  WEBCAMPRIVATE_SET,
+  WEBCAMPRIVATE_RESET,
+  WEBCAMPRIVATE_GET,
   // Last entry: Add new entries above and ensure to update
   // tools/metrics/histograms/histograms/histograms.xml.
   ENUM_BOUNDARY