Move SessionID, CaptureVisibleTabFunction to WebContents.

chrome/browser/sessions/session_id.h

 // 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_SESSIONS_SESSION_ID_H_
 #define CHROME_BROWSER_SESSIONS_SESSION_ID_H_
 
 #include "base/basictypes.h"
 
 class Browser;
-class TabContents;
+
+namespace content {
+class WebContents;
+}
 
 // Uniquely identifies a tab or window for the duration of a session.
 class SessionID {
  public:
   typedef int32 id_type;
 
   SessionID();
   ~SessionID() {}
 
   // This value is immutable for a given tab. It will be unique across Chrome
   // within the current session, but may be re-used across sessions. Returns -1
   // for NULL, and will never return -1 for a valid tab.
-  static id_type IdForTab(const TabContents* tab);
+  static id_type IdForTab(const content::WebContents* tab);
 
   // If the tab has ever been attached to a window, this is the value of
   // Browser::session_id().id() for some Browser object. Returns -1 for NULL, or
   // another value that's not equal to any Browser's id for a tab that has never
   // been attached to a window. IdForWindowContainingTab() returns the old
   // window for a tab that's currently being dragged between windows.
-  static id_type IdForWindowContainingTab(const TabContents* tab);
+  static id_type IdForWindowContainingTab(const content::WebContents* tab);
 
   // Returns the underlying id.
   void set_id(id_type id) { id_ = id; }
   id_type id() const { return id_; }
 
  private:
   id_type id_;
 };
 
 #endif  // CHROME_BROWSER_SESSIONS_SESSION_ID_H_