MacViews: Support continuous scrolling and horizontal scrolling

ui/views/controls/scrollbar/base_scroll_bar.cc

 // 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.
 
 #include "ui/views/controls/scrollbar/base_scroll_bar.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/callback.h"
 #include "base/compiler_specific.h"
@@ skipping 176 matching lines @@
       break;
   }
   if (amount != SCROLL_NONE) {
     ScrollByAmount(amount);
     return true;
   }
   return false;
 }
 
 bool BaseScrollBar::OnMouseWheel(const ui::MouseWheelEvent& event) {
-  ScrollByContentsOffset(event.y_offset());
+  ScrollByContentsOffset(IsHorizontal() ? event.x_offset() : event.y_offset());

[tapted, 2014/09/02 09:10:25]

Maybe this should be doing `return OnScroll(event.x_offset(),
event.y_offset());`

[Andre, 2014/09/02 17:05:05]

Done.
But I kept the return true because OnScroll can return false, which might cause
unwanted behavior
change in case of nested scroll views.

   return true;
 }
 
 void BaseScrollBar::OnGestureEvent(ui::GestureEvent* event) {
   // If a fling is in progress, then stop the fling for any incoming gesture
   // event (except for the GESTURE_END event that is generated at the end of the
   // fling).
   if (scroll_animator_.get() && scroll_animator_->is_scrolling() &&
       (event->type() != ui::ET_GESTURE_END ||
        event->details().touch_points() > 1)) {
@@ skipping 300 matching lines @@
     thumb_position = thumb_position - (thumb_->GetSize() / 2);
   return (thumb_position * contents_size_) / GetTrackSize();
 }
 
 void BaseScrollBar::SetThumbTrackState(CustomButton::ButtonState state) {
   thumb_track_state_ = state;
   SchedulePaint();
 }
 
 }  // namespace views