Add per-tab "JavaScript enabled" preference.

chrome/browser/ui/tab_contents/per_tab_prefs_tab_helper.h

Index: chrome/browser/ui/tab_contents/per_tab_prefs_tab_helper.h
diff --git a/chrome/browser/ui/tab_contents/per_tab_prefs_tab_helper.h b/chrome/browser/ui/tab_contents/per_tab_prefs_tab_helper.h
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index 0000000000000000000000000000000000000000..5784dd145177475e2020435200b2c63c61d4675a
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+++ b/chrome/browser/ui/tab_contents/per_tab_prefs_tab_helper.h
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+// Copyright (c) 2011 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_UI_TAB_CONTENTS_PER_TAB_PREFS_TAB_HELPER_H_
+#define CHROME_BROWSER_UI_TAB_CONTENTS_PER_TAB_PREFS_TAB_HELPER_H_
+#pragma once
+
+#include "chrome/browser/prefs/pref_change_registrar.h"
+#include "content/browser/tab_contents/tab_contents_observer.h"
+
+class PrefService;
+class TabContentsWrapper;
+struct WebPreferences;
+
+// Per-tab class to override user preferences.
+class PerTabPrefsTabHelper : public TabContentsObserver {
+ public:
+  explicit PerTabPrefsTabHelper(TabContentsWrapper* tab_contents);
+  virtual ~PerTabPrefsTabHelper();
+
+  PrefService* prefs() { return prefs_.get(); }
+
+  void OverrideWebPreferences(WebPreferences* prefs);
+
+ private:
+  void RegisterPerTabUserPrefs(PrefService* prefs);
+
+  // TabContentsObserver overrides:
+  virtual void TabContentsDestroyed(TabContents* tab) OVERRIDE;
+
+  // Our owning TabContentsWrapper.
+  TabContentsWrapper* wrapper_;
+
+  scoped_ptr<PrefService> prefs_;
+  PrefChangeRegistrar pref_change_registrar_;
+
+  DISALLOW_COPY_AND_ASSIGN(PerTabPrefsTabHelper);
+};
+
+#endif  // CHROME_BROWSER_UI_TAB_CONTENTS_PER_TAB_PREFS_TAB_HELPER_H_