Create CoreTabHelper, move remaining core TCW functionality into it.

chrome/browser/ui/snapshot_tab_helper.h

+// 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_SNAPSHOT_TAB_HELPER_H_
+#define CHROME_BROWSER_UI_SNAPSHOT_TAB_HELPER_H_
+#pragma once
+
+#include "content/browser/tab_contents/tab_contents_observer.h"
+
+class SkBitmap;
+class TabContentsWrapper;
+
+// Per-tab class to handle snapshot functionality.
+class SnapshotTabHelper : public TabContentsObserver {
+ public:
+  explicit SnapshotTabHelper(TabContentsWrapper* wrapper);
+  virtual ~SnapshotTabHelper();
+
+  // Captures a snapshot of the page.
+  void CaptureSnapshot();
+
+ private:
+  // TabContentsObserver overrides:
+  virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
+
+  // Internal helpers ----------------------------------------------------------
+
+  // Message handler.
+  void OnSnapshot(const SkBitmap& bitmap);
+
+  // Our owning TabContentsWrapper.
+  TabContentsWrapper* wrapper_;
+
+  DISALLOW_COPY_AND_ASSIGN(SnapshotTabHelper);
+};
+
+#endif  // CHROME_BROWSER_UI_SNAPSHOT_TAB_HELPER_H_