[protector] Support for collapsing multiple changes into a single one.

chrome/browser/protector/composite_settings_change.h

Index: chrome/browser/protector/composite_settings_change.h
diff --git a/chrome/browser/protector/composite_settings_change.h b/chrome/browser/protector/composite_settings_change.h
new file mode 100644
index 0000000000000000000000000000000000000000..727dd9310f3eaf7d77ebfdb20402e9e7acb6660f
--- /dev/null
+++ b/chrome/browser/protector/composite_settings_change.h
@@ -0,0 +1,52 @@
+// 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_PROTECTOR_COMPOSITE_SETTINGS_CHANGE_H_
+#define CHROME_BROWSER_PROTECTOR_COMPOSITE_SETTINGS_CHANGE_H_
+#pragma once
+
+#include <queue>
+
+#include "base/memory/scoped_vector.h"
+#include "chrome/browser/protector/base_setting_change.h"
+
+namespace protector {
+
+// Class for tracking multiple settings changes as a single change.
+class CompositeSettingsChange : public BaseSettingChange {
+ public:
+  CompositeSettingsChange();
+  virtual ~CompositeSettingsChange();
+
+  // BaseSettingChange overrides:
+  virtual CompositeSettingsChange* MergeWith(BaseSettingChange* other) OVERRIDE;
+  virtual bool Contains(const BaseSettingChange* other) const OVERRIDE;
+  virtual void Apply(Browser* browser) OVERRIDE;
+  virtual void Discard(Browser* browser) OVERRIDE;
+  virtual void Timeout() OVERRIDE;
+  virtual int GetBadgeIconID() const OVERRIDE;
+  virtual int GetMenuItemIconID() const OVERRIDE;
+  virtual int GetBubbleIconID() const OVERRIDE;
+  virtual string16 GetBubbleTitle() const OVERRIDE;
+  virtual string16 GetBubbleMessage() const OVERRIDE;
+  virtual string16 GetApplyButtonText() const OVERRIDE;
+  virtual string16 GetDiscardButtonText() const OVERRIDE;
+  virtual DisplayName GetApplyDisplayName() const OVERRIDE;
+  virtual GURL GetNewSettingURL() const OVERRIDE;
+  virtual bool CanBeMerged() const OVERRIDE;
+
+ private:
+  // Vector with all merged changes.
+  ScopedVector<BaseSettingChange> changes_;
+
+  // Display names of merged changes, sorted by their priority. The name with
+  // the highest priority is picked.
+  std::priority_queue<DisplayName> apply_names_;
+
+  DISALLOW_COPY_AND_ASSIGN(CompositeSettingsChange);
+};
+
+}  // namespace protector
+
+#endif  // CHROME_BROWSER_PROTECTOR_COMPOSITE_SETTINGS_CHANGE_H_