Route Scroll events through a cc::InputHandler

ui/views/controls/scroll_view.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/scroll_view.h"
 
 #include "base/feature_list.h"
 #include "base/logging.h"
 #include "base/macros.h"
+#include "ui/compositor/overscroll/ui_scroll_input_manager.h"
 #include "ui/events/event.h"
 #include "ui/gfx/canvas.h"
 #include "ui/native_theme/native_theme.h"
 #include "ui/views/background.h"
 #include "ui/views/border.h"
 #include "ui/views/controls/focus_ring.h"
 #include "ui/views/style/platform_style.h"
 #include "ui/views/widget/widget.h"
 
 namespace views {
@@ skipping 433 matching lines @@
     processed = horiz_sb_->OnMouseWheel(e) || processed;
 
   return processed;
 }
 
 void ScrollView::OnScrollEvent(ui::ScrollEvent* event) {
 #if defined(OS_MACOSX)
   if (!contents_)
     return;
 
-  // TODO(tapted): Send |event| to a cc::InputHandler. For now, there's nothing
-  // to do because Widget::OnScrollEvent() will automatically process an
-  // unhandled ScrollEvent as a MouseWheelEvent.
+  ui::UIScrollInputManager* compositor_scroller =
+      GetWidget()->GetCompositor()->scroll_input_manager();
+  DCHECK(compositor_scroller);
+  if (compositor_scroller->OnScrollEvent(*event, contents_->layer())) {
+    event->SetHandled();
+    event->StopPropagation();
+  }
 
   // A direction might not be known when the event stream starts, notify both
   // scrollbars that they may be about scroll, or that they may need to cancel
   // UI feedback once the scrolling direction is known.
   if (horiz_sb_)
     horiz_sb_->ObserveScrollEvent(*event);
   if (vert_sb_)
     vert_sb_->ObserveScrollEvent(*event);
 #endif
 }
@@ skipping 62 matching lines @@
   }
   // No view, or the view didn't return a valid amount.
   if (is_page) {
     return is_horizontal ? contents_viewport_->width() :
                            contents_viewport_->height();
   }
   return is_horizontal ? contents_viewport_->width() / 5 :
                          contents_viewport_->height() / 5;
 }
 
+void ScrollView::OnScrollEventFromScrollBar(ui::ScrollEvent* event) {
+  // Note that |event| can't be used for hit-testing in the cc::InputHandler
+  // as-is, since it will hit a scroll bar Layer. Layer scrolling supports that,
+  // but only if the scroll bar track and thumb Layers implement
+  // cc::ScrollbarLayerInterface. Creating one of those requires a cc::ScrollBar
+  // instance which is more than views:: really needs to care about. The
+  // following works because ScrollView explicitly passes the Layer to scroll.
+  OnScrollEvent(event);
+}
+
 void ScrollView::SetHeaderOrContents(View* parent,
                                      View* new_view,
                                      View** member) {
   if (*member == new_view)
     return;
 
   delete *member;
   *member = new_view;
   if (*member)
     parent->AddChildView(*member);
@@ skipping 223 matching lines @@
 
 VariableRowHeightScrollHelper::RowInfo
     FixedRowHeightScrollHelper::GetRowInfo(int y) {
   if (y < top_margin_)
     return RowInfo(0, top_margin_);
   return RowInfo((y - top_margin_) / row_height_ * row_height_ + top_margin_,
                  row_height_);
 }
 
 }  // namespace views