Exports gesture manager to a separate file and adds its unittests.

athena/home/home_card_gesture_manager.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 ATHENA_HOME_HOME_CARD_GESTURE_MANAGER_H_
+#define ATHENA_HOME_HOME_CARD_GESTURE_MANAGER_H_
+
+#include "athena/home/public/home_card.h"
+#include "athena/athena_export.h"
+#include "ui/gfx/geometry/rect.h"
+
+namespace ui {
+class GestureEvent;
+}
+
+namespace athena {
+
+// Handles the touch gestures over the home card.
+class ATHENA_EXPORT HomeCardGestureManager {
+ public:
+  class Delegate {
+   public:
+    // Called when the gesture has ended. The state of the home card will
+    // end up with |final_state|.
+    virtual void OnGestureEnded(HomeCard::State final_state) = 0;
+
+    // Called when the gesture position is updated so that |delegate| should
+    // update the visual. The arguments represent the state of the current
+    // gesture position is switching from |from_state| to |to_state|, and
+    // the level of the progress is at |progress|, which is 0 to 1.
+    // |from_state| and |to_state| could be same. For example, if the user moves
+    // the finger down to the bottom of the screen, both states are MINIMIZED.
+    // In that case |progress| is 0.
+    virtual void OnGestureProgressed(
+        HomeCard::State from_state,
+        HomeCard::State to_state,
+        float progress) = 0;
+  };
+
+  HomeCardGestureManager(Delegate* delegate,
+                         const gfx::Rect& screen_bounds);
+  ~HomeCardGestureManager();
+
+  void ProcessGestureEvent(ui::GestureEvent* event);
+
+ private:
+  // Get the closest state from the last position.
+  HomeCard::State GetClosestState() const;
+
+  // Update the current position and emits OnGestureProgressed().
+  void UpdateScrollState(const ui::GestureEvent& event);
+
+  Delegate* delegate_;  // Not owned.
+  HomeCard::State last_state_;
+
+  // The offset from the top edge of the home card and the initial position of
+  // gesture.
+  int y_offset_;
+
+  // The estimated height of the home card after the last touch event.
+  int last_estimated_height_;
+
+  // The bounds of the screen to compute the home card bounds.
+  gfx::Rect screen_bounds_;
+
+  DISALLOW_COPY_AND_ASSIGN(HomeCardGestureManager);
+};
+
+}  // namespace athena
+
+#endif  // ATHENA_HOME_HOME_CARD_GESTURE_MANAGER_H_