[protector] Added SessionStartupChange for representing changes in SessionStartupPref.

chrome/browser/protector/base_setting_change.h

Index: chrome/browser/protector/base_setting_change.h
diff --git a/chrome/browser/protector/base_setting_change.h b/chrome/browser/protector/base_setting_change.h
index 098d6f18b6e4f12b548712677bf8c3b40748ae41..fa1a4596245c025ef991180902c37fe3ab72a808 100644
--- a/chrome/browser/protector/base_setting_change.h
+++ b/chrome/browser/protector/base_setting_change.h
@@ -15,6 +15,7 @@
 class Browser;
 class Profile;
 class TemplateURL;
+struct SessionStartupPref;
 
 namespace protector {
 
@@ -87,6 +88,12 @@ BaseSettingChange* CreateDefaultSearchProviderChange(
     const TemplateURL* actual,
     TemplateURL* backup);
 
+// Allocates and initializes BaseSettingChange implementation for session
+// startup setting. Reports corresponding histograms.
+BaseSettingChange* CreateSessionStartupChange(
+    const SessionStartupPref& actual,
+    const SessionStartupPref& backup);
+
 }  // namespace protector
 
 #endif  // CHROME_BROWSER_PROTECTOR_BASE_SETTING_CHANGE_H_