[Contextual Search] Remove opt-in code.

chrome/browser/search/contextual_search_promo_source_android.h

-// Copyright 2014 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_SEARCH_CONTEXTUAL_SEARCH_PROMO_SOURCE_ANDROID_H_
-#define CHROME_BROWSER_SEARCH_CONTEXTUAL_SEARCH_PROMO_SOURCE_ANDROID_H_
-
-#include "base/basictypes.h"
-#include "base/compiler_specific.h"
-#include "content/public/browser/url_data_source.h"
-
-// Serves HTML for displaying the contextual search first-run promo.
-class ContextualSearchPromoSourceAndroid : public content::URLDataSource {
- public:
-  ContextualSearchPromoSourceAndroid();
-  ~ContextualSearchPromoSourceAndroid() override;
-
- protected:
-  // Overridden from content::URLDataSource:
-  void StartDataRequest(
-      const std::string& path_and_query,
-      int render_process_id,
-      int render_frame_id,
-      const content::URLDataSource::GotDataCallback& callback) override;
-  std::string GetSource() const override;
-  std::string GetMimeType(const std::string& path_and_query) const override;
-  bool ShouldDenyXFrameOptions() const override;
-  bool ShouldAddContentSecurityPolicy() const override;
-
-  // Sends unmodified resource bytes.
-  void SendResource(
-      int resource_id,
-      const content::URLDataSource::GotDataCallback& callback);
-
-  // Sends the config JS resource.
-  void SendConfigResource(
-      const content::URLDataSource::GotDataCallback& callback);
-
-  // Sends HTML with localized strings.
-  void SendHtmlWithStrings(
-    const content::URLDataSource::GotDataCallback& callback);
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(ContextualSearchPromoSourceAndroid);
-};
-
-#endif  // CHROME_BROWSER_SEARCH_CONTEXTUAL_SEARCH_PROMO_SOURCE_ANDROID_H_