MD Settings: handle zoom as floats to fix ghost zoom level issue

chrome/browser/extensions/api/settings_private/settings_private_delegate.h

 // Copyright 2015 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_API_SETTINGS_PRIVATE_SETTINGS_PRIVATE_DELEGATE_H_
 #define CHROME_BROWSER_EXTENSIONS_API_SETTINGS_PRIVATE_SETTINGS_PRIVATE_DELEGATE_H_
 
 #include <map>
 #include <memory>
 #include <string>
@@ skipping 30 matching lines @@
   // Gets the value of the pref with the given |name|.
   virtual std::unique_ptr<base::Value> GetPref(const std::string& name);
 
   // Gets the values of all whitelisted prefs.
   virtual std::unique_ptr<base::Value> GetAllPrefs();
 
   // Gets the value.
   virtual std::unique_ptr<base::Value> GetDefaultZoomPercent();
 
   // Sets the pref.
-  virtual PrefsUtil::SetPrefResult SetDefaultZoomPercent(int percent);
+  virtual PrefsUtil::SetPrefResult SetDefaultZoomPercent(double percent);
 
  protected:
   Profile* profile_;  // weak; not owned by us
   std::unique_ptr<PrefsUtil> prefs_util_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(SettingsPrivateDelegate);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_SETTINGS_PRIVATE_SETTINGS_PRIVATE_DELEGATE_H_