Refactor the home card structure and introduce animation.

athena/home/home_card_gesture_manager.cc

 // 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.
 
 #include "athena/home/home_card_gesture_manager.h"
 
 #include "athena/home/home_card_constants.h"
 #include "ui/events/event.h"
 
 namespace athena {
@@ skipping 81 matching lines @@
   float bigger_height = kHomeCardHeight;
   if (last_estimated_height_ > kHomeCardHeight) {
     state = HomeCard::VISIBLE_CENTERED;
     smaller_height = kHomeCardHeight;
     bigger_height = screen_bounds_.height();
   }
 
   // The finger is between two states.
   float progress = (last_estimated_height_ - smaller_height) /
       (bigger_height - smaller_height);
+  progress = std::min(1.0f, std::max(0.0f, progress));
 
   if (last_state_ == state) {
     if (event.details().scroll_y() > 0) {
       state = static_cast<HomeCard::State>(state + 1);
       progress = 1.0f - progress;
     } else {
       last_state_ = static_cast<HomeCard::State>(last_state_ + 1);
     }
   }
   delegate_->OnGestureProgressed(last_state_, state, progress);
   last_state_ = state;
 }
 
 }  // namespace athena