MacViews: Support continuous scrolling and horizontal scrolling

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/logging.h"
 #include "ui/events/event.h"
 #include "ui/gfx/canvas.h"
 #include "ui/native_theme/native_theme.h"
@@ skipping 336 matching lines @@
     processed = vert_sb_->OnKeyPressed(event);
 
   if (!processed && horiz_sb_->visible())
     processed = horiz_sb_->OnKeyPressed(event);
 
   return processed;
 }
 
 bool ScrollView::OnMouseWheel(const ui::MouseWheelEvent& e) {
   bool processed = false;
-  // Give vertical scrollbar priority
+
   if (vert_sb_->visible())
     processed = vert_sb_->OnMouseWheel(e);
 
-  if (!processed && horiz_sb_->visible())
-    processed = horiz_sb_->OnMouseWheel(e);
+  if (horiz_sb_->visible())
+    processed = horiz_sb_->OnMouseWheel(e) || processed;

[sky, 2014/09/02 18:25:54]

Why this change? Doesn't this mean we always send to both vert/horizontal even
if vertical processed it?

[Andre, 2014/09/02 18:30:52]

Yes, BaseScrollBar::OnMouseWheel always returns true so the horizontal never
gets a chance.
Also, some events may have both x and y offsets.

 
   return processed;
 }
 
 void ScrollView::OnMouseEntered(const ui::MouseEvent& event) {
   if (horiz_sb_)
     horiz_sb_->OnMouseEnteredScrollView(event);
   if (vert_sb_)
     vert_sb_->OnMouseEnteredScrollView(event);
 }
@@ skipping 262 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