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diff --git a/chrome/browser/instant/instant_model.h b/chrome/browser/instant/instant_model.h
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+++ b/chrome/browser/instant/instant_model.h
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+// Copyright 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_INSTANT_INSTANT_MODEL_H_
+#define CHROME_BROWSER_INSTANT_INSTANT_MODEL_H_
+
+#include "base/basictypes.h"
+#include "base/observer_list.h"
+#include "chrome/common/instant_types.h"
+
+class InstantController;
+class InstantModelObserver;
+class TabContents;
+
+// Holds state that is important to any views concerned with visibility and
+// layout of the Instant preview.
+class InstantModel {
+ public:
+  enum DisplayState {
+    // When the preview contents are out of date, the preview should not be
+    // shown.
+    NOT_READY,
+
+    // When the preview contents is updated and ready for display its state
+    // transitions to |QUERY_RESULTS|.
+    QUERY_RESULTS,
+  };
+
+  explicit InstantModel(InstantController* controller);
+  ~InstantModel();
+
+  void SetDisplayState(DisplayState display,
+                       int height, InstantSizeUnits height_units);
+  DisplayState display_state() const { return display_state_; }
+  bool is_ready() const { return display_state_ != NOT_READY; }
+  int height() const { return height_; }
+  InstantSizeUnits height_units() const { return height_units_; }
+
+  void SetPreviewContents(TabContents* preview_contents);
+  TabContents* GetPreviewContents() const;
+
+  // Add, remove, check observers.
+  void AddObserver(InstantModelObserver* observer) const;
+  void RemoveObserver(InstantModelObserver* observer) const;
+  bool HasObserver(InstantModelObserver* observer) const;
+
+ private:
+  // |QUERY_RESULTS| if the preview should be displayed. Guaranteed to be
+  // |NOT_READY| if InstantController::IsOutOfDate() is true.
+  DisplayState display_state_;
+  int height_;
+  InstantSizeUnits height_units_;
+
+  // Weak.  Remembers the last set preview contents to detect changes.
+  // Actual preview contents is fetched from the |controller_| as this
+  // may not always reflect the actual preview in effect.
+  TabContents* preview_contents_;
+
+  // Weak.  The controller currently holds some model state.
+  // TODO(dhollowa): Remove this, transfer all model state to InstantModel.
+  InstantController* const controller_;
+
+  // Observers.
+  mutable ObserverList<InstantModelObserver> observers_;
+
+  DISALLOW_IMPLICIT_CONSTRUCTORS(InstantModel);
+};
+
+#endif  // CHROME_BROWSER_INSTANT_INSTANT_MODEL_H_