Remove not needed ExtensionUpdater::default_params_ and its setter.

chrome/browser/extensions/updater/extension_updater.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_UPDATER_EXTENSION_UPDATER_H_
 #define CHROME_BROWSER_EXTENSIONS_UPDATER_EXTENSION_UPDATER_H_
 
 #include <list>
 #include <map>
 #include <set>
@@ skipping 101 matching lines @@
 
   // Starts an update check right now, instead of waiting for the next
   // regularly scheduled check or a pending check from CheckSoon().
   void CheckNow(const CheckParams& params);
 
   // Returns true iff CheckSoon() has been called but the update check
   // hasn't been performed yet.  This is used mostly by tests; calling
   // code should just call CheckSoon().
   bool WillCheckSoon() const;
 
-  // Changes the params that are used for the automatic periodic update checks,
-  // as well as for explicit calls to CheckSoon.
-  void set_default_check_params(const CheckParams& params) {
-    default_params_ = params;

[asargent_no_longer_on_chrome, 2016/01/25 23:11:16]

Can we also kill the default_params_ variable itself, and just pass a temporary
CheckParams() in the calls we make to CheckNow in extension_updater.cc? It
doesn't look like we hold any pointers/references to members of the CheckParams
passed into CheckNow beyond the lifetime of the call. 

[lazyboy, 2016/01/25 23:46:58]

Even better, thanks.
Done.

-  }
-
   // Overrides the extension cache with |extension_cache| for testing.
   void SetExtensionCacheForTesting(ExtensionCache* extension_cache);
 
   // Stop the timer to prevent scheduled updates for testing.
   void StopTimerForTesting();
 
  private:
   friend class ExtensionUpdaterTest;
   friend class ExtensionUpdaterFileHandler;
 
@@ skipping 142 matching lines @@
   std::map<std::string, ThrottleInfo> throttle_info_;
 
   base::WeakPtrFactory<ExtensionUpdater> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionUpdater);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_UPDATER_EXTENSION_UPDATER_H_