Add FrameNavigationEntry class.

content/browser/frame_host/frame_navigation_entry.h

Index: content/browser/frame_host/frame_navigation_entry.h
diff --git a/content/browser/frame_host/frame_navigation_entry.h b/content/browser/frame_host/frame_navigation_entry.h
new file mode 100644
index 0000000000000000000000000000000000000000..622b6826834aa55a5556f4db5a48447d5788edaf
--- /dev/null
+++ b/content/browser/frame_host/frame_navigation_entry.h
@@ -0,0 +1,64 @@
+// Copyright 2015 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 CONTENT_BROWSER_FRAME_HOST_FRAME_NAVIGATION_ENTRY_H_
+#define CONTENT_BROWSER_FRAME_HOST_FRAME_NAVIGATION_ENTRY_H_
+
+#include "base/basictypes.h"
+#include "base/memory/ref_counted.h"
+#include "content/browser/site_instance_impl.h"
+#include "content/public/common/referrer.h"
+
+namespace content {
+
+// Represents a session history item for a particular frame.
+//
+// This class is currently owned by a single NavigationEntry and only tracks the
+// main frame.
+//
+// TODO(creis): Keep a tree of FrameNavigationEntries in each NavigationEntry,
+// one per frame.  FrameNavigationEntries may be shared across NavigationEntries
+// if the frame hasn't changed.
+class CONTENT_EXPORT FrameNavigationEntry {
+ public:
+  FrameNavigationEntry();
+  FrameNavigationEntry(SiteInstanceImpl* site_instance,
+                       const GURL& url,
+                       const Referrer& referrer);
+  virtual ~FrameNavigationEntry();
+
+  // The SiteInstance responsible for rendering this frame.  All frames sharing
+  // a SiteInstance must live in the same process.  This is a refcounted pointer
+  // that keeps the SiteInstance (not necessarily the process) alive as long as
+  // this object remains in the session history.
+  void set_site_instance(SiteInstanceImpl* site_instance) {
+    site_instance_ = site_instance;
+  }
+  SiteInstanceImpl* site_instance() const { return site_instance_.get(); }
+
+  // The actual URL loaded in the frame.  This is in contrast to the virtual
+  // URL, which is shown to the user.
+  // TODO(creis): Move virtual URL and related members to FrameNavigationEntry.
+  void set_url(const GURL& url) { url_ = url; }
+  const GURL& url() const { return url_; }
+
+  // The referring URL.  Can be empty.
+  void set_referrer(const Referrer& referrer) { referrer_ = referrer; }
+  const Referrer& referrer() const { return referrer_; }
+
+ private:
+  // TODO(creis): These fields have implications for session restore.  This is
+  // currently managed by NavigationEntry, but the logic will move here.
+
+  // See the accessors above for descriptions.
+  scoped_refptr<SiteInstanceImpl> site_instance_;
+  GURL url_;
+  Referrer referrer_;
+
+  // Copy and assignment is explicitly allowed for this class.
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_FRAME_HOST_FRAME_NAVIGATION_ENTRY_H_