[fsp] Add histograms for reading files.

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 812 matching lines @@
   LEDGER_BATCHEXECUTE,
   FILESYSTEMPROVIDERINTERNAL_OPENFILEREQUESTEDSUCCESS,
   FILESYSTEMPROVIDERINTERNAL_OPENFILEREQUESTEDERROR,
   FILESYSTEMPROVIDERINTERNAL_CLOSEFILEREQUESTEDSUCCESS,
   FILESYSTEMPROVIDERINTERNAL_CLOSEFILEREQUESTEDERROR,
   SYNCEDNOTIFICATIONSPRIVATE_GETINITIALDATA,
   SYNCEDNOTIFICATIONSPRIVATE_UPDATENOTIFICATION,
   SYNCEDNOTIFICATIONSPRIVATE_SETRENDERCONTEXT,
   IDENTITY_GETACCOUNTS,
   FILEBROWSERPRIVATE_RESOLVEISOLATEDENTRIES,
+  FILESYSTEMPROVIDERINTERNAL_READFILEREQUESTEDSUCCESS,
+  FILESYSTEMPROVIDERINTERNAL_READFILEREQUESTEDERROR,
   // Last entry: Add new entries above and ensure to update
   // tools/metrics/histograms/histograms/histograms.xml.
   ENUM_BOUNDARY
 };
 
 }  // namespace functions
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_EXTENSION_FUNCTION_HISTOGRAM_VALUE_H_