New tabCapture.captureOffscreenTab API, initially for Presentation API 1UA mode

extensions/browser/extension_function_histogram_value.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef EXTENSIONS_BROWSER_EXTENSION_FUNCTION_HISTOGRAM_VALUE_H_
 #define EXTENSIONS_BROWSER_EXTENSION_FUNCTION_HISTOGRAM_VALUE_H_
 
 namespace extensions {
 namespace functions {
 
@@ skipping 1130 matching lines @@
   CERTIFICATEPROVIDERINTERNAL_REPORTSIGNATURE,
   CERTIFICATEPROVIDERINTERNAL_REPORTCERTIFICATES,
   BLUETOOTHPRIVATE_PAIR,
   EASYUNLOCKPRIVATE_FINDSETUPCONNECTION,
   RESOURCESPRIVATE_GETSTRINGS,
   USB_GETCONFIGURATIONS,
   EASYUNLOCKPRIVATE_SETUPCONNECTIONSTATUS,
   EASYUNLOCKPRIVATE_SETUPCONNECTIONDISCONNECT,
   EASYUNLOCKPRIVATE_SETUPCONNECTIONSEND,
   DATAREDUCTIONPROXY_GETDATAUSAGE,
+  TABCAPTURE_CAPTUREOFFSCREENTAB,
   // Last entry: Add new entries above, then run:
   // python tools/metrics/histograms/update_extension_histograms.py
   ENUM_BOUNDARY
 };
 
 }  // namespace functions
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_EXTENSION_FUNCTION_HISTOGRAM_VALUE_H_