[ash-md] Adds support for Z-order iteration in views::View

ui/views/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.
 
 #define _USE_MATH_DEFINES // For VC++ to get M_PI. This has to be first.
 
 #include "ui/views/view.h"
 
 #include <algorithm>
 #include <cmath>
@@ skipping 443 matching lines @@
 
     for (ViewObserver& observer : observers_)
       observer.OnViewEnabledChanged(this);
   }
 }
 
 void View::OnEnabledChanged() {
   SchedulePaint();
 }
 
+View::Views View::GetChildrenOrderedByVisualOrder() {
+  return children_;
+}
+
 // Transformations -------------------------------------------------------------
 
 gfx::Transform View::GetTransform() const {
   if (!layer())
     return gfx::Transform();
 
   gfx::Transform transform = layer()->transform();
   gfx::ScrollOffset scroll_offset = layer()->CurrentScrollOffset();
   transform.Translate(-scroll_offset.x(), -scroll_offset.y());
   return transform;
@@ skipping 436 matching lines @@
   return true;
 }
 
 View* View::GetTooltipHandlerForPoint(const gfx::Point& point) {
   // TODO(tdanderson): Move this implementation into ViewTargetDelegate.
   if (!HitTestPoint(point) || !CanProcessEventsWithinSubtree())
     return NULL;
 
   // Walk the child Views recursively looking for the View that most
   // tightly encloses the specified point.
-  for (int i = child_count() - 1; i >= 0; --i) {
-    View* child = child_at(i);
+  View::Views children = GetChildrenOrderedByVisualOrder();
+  DCHECK_EQ(child_count(), static_cast<int>(children.size()));
+  for (int i = children.size() - 1; i >= 0; --i) {
+    View* child = children[i];
     if (!child->visible())
       continue;
 
     gfx::Point point_in_child_coords(point);
     ConvertPointToTarget(this, child, &point_in_child_coords);
     View* handler = child->GetTooltipHandlerForPoint(point_in_child_coords);
     if (handler)
       return handler;
   }
   return this;
@@ skipping 498 matching lines @@
 
     if (focus_manager)
       RegisterPendingAccelerators();
   }
 }
 
 // Painting --------------------------------------------------------------------
 
 void View::PaintChildren(const ui::PaintContext& context) {
   TRACE_EVENT1("views", "View::PaintChildren", "class", GetClassName());
-  for (int i = 0, count = child_count(); i < count; ++i)
-    if (!child_at(i)->layer())
-      child_at(i)->Paint(context);
+  View::Views children = GetChildrenOrderedByVisualOrder();
+  DCHECK_EQ(child_count(), static_cast<int>(children.size()));
+  for (int i = 0, count = children.size(); i < count; ++i) {

[sky, 2016/12/13 23:40:56]

Use range based for-loop?

[varkha, 2016/12/19 20:35:44]

Done. I will try to get the rest of the similar iterations in view.cc and
view_targeter_delegate.cc to be like this as well (in a separate CL).

[varkha, 2016/12/19 20:56:15]

Posted https://codereview.chromium.org/2583343003 for the rest of the similar
iterations in this file.

+    View* child = children[i];
+    if (!child->layer())
+      child->Paint(context);
+  }
 }
 
 void View::OnPaint(gfx::Canvas* canvas) {
   TRACE_EVENT1("views", "View::OnPaint", "class", GetClassName());
   OnPaintBackground(canvas);
   OnPaintBorder(canvas);
 }
 
 void View::OnPaintBackground(gfx::Canvas* canvas) {
   if (background_.get()) {
@@ skipping 128 matching lines @@
 }
 
 void View::ReorderChildLayers(ui::Layer* parent_layer) {
   if (layer() && layer() != parent_layer) {
     DCHECK_EQ(parent_layer, layer()->parent());
     parent_layer->StackAtBottom(layer());
   } else {
     // Iterate backwards through the children so that a child with a layer
     // which is further to the back is stacked above one which is further to
     // the front.
-    for (Views::reverse_iterator it(children_.rbegin());
-         it != children_.rend(); ++it) {
-      (*it)->ReorderChildLayers(parent_layer);
-    }
+    View::Views children = GetChildrenOrderedByVisualOrder();
+    DCHECK_EQ(child_count(), static_cast<int>(children.size()));
+    for (int i = children.size() - 1; i >= 0; --i)

[sky, 2016/12/13 23:40:56]

I think a reverse iterator is safer here.

[varkha, 2016/12/19 20:35:44]

Done.

+      children[i]->ReorderChildLayers(parent_layer);
   }
 }
 
 // Input -----------------------------------------------------------------------
 
 View::DragInfo* View::GetDragInfo() {
   return parent_ ? parent_->GetDragInfo() : NULL;
 }
 
 // Focus -----------------------------------------------------------------------
@@ skipping 843 matching lines @@
   // Message the RootView to do the drag and drop. That way if we're removed
   // the RootView can detect it and avoid calling us back.
   gfx::Point widget_location(event.location());
   ConvertPointToWidget(this, &widget_location);
   widget->RunShellDrag(this, data, widget_location, drag_operations, source);
   // WARNING: we may have been deleted.
   return true;
 }
 
 }  // namespace views