Only apply extension throttling quota to sync, not local.

chrome/browser/extensions/extension_function.h

 // Copyright (c) 2012 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 CHROME_BROWSER_EXTENSIONS_EXTENSION_FUNCTION_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_FUNCTION_H_
 #pragma once
 
 #include <list>
 #include <string>
@@ skipping 66 matching lines @@
   virtual IOThreadExtensionFunction* AsIOThreadExtensionFunction();
 
   // Execute the API. Clients should initialize the ExtensionFunction using
   // SetArgs(), set_request_id(), and the other setters before calling this
   // method. Derived classes should be ready to return GetResultValue() and
   // GetError() before returning from this function.
   // Note that once Run() returns, dispatcher() can be NULL, so be sure to
   // NULL-check.
   virtual void Run();
 
+  // Gets whether quota should be applied to this individual function
+  // invocation. This is different to GetQuotaLimitHeuristics which is only
+  // invoked once and then cached.
+  //
+  // Returns false by default.
+  virtual bool ShouldSkipQuotaLimiting() const;
+
   // Optionally adds one or multiple QuotaLimitHeuristic instances suitable for
   // this function to |heuristics|. The ownership of the new QuotaLimitHeuristic
   // instances is passed to the owner of |heuristics|.
   // No quota limiting by default.
+  //
+  // Only called once per lifetime of the ExtensionsQuotaService.
   virtual void GetQuotaLimitHeuristics(
       QuotaLimitHeuristics* heuristics) const {}
 
   // Called when the quota limit has been exceeded. The default implementation
   // returns an error.
   virtual void OnQuotaExceeded();
 
   // Specifies the raw arguments to the function, as a JSON value.
   virtual void SetArgs(const base::ListValue* args);
 
@@ skipping 302 matching lines @@
  public:
   SyncIOThreadExtensionFunction();
 
   virtual void Run() OVERRIDE;
 
  protected:
   virtual ~SyncIOThreadExtensionFunction();
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_FUNCTION_H_