Create a unified UIElement interface for Widget, View and Window.

ash/devtools/view_element.cc

+// Copyright 2017 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 "ash/devtools/view_element.h"
+
+#include "ash/devtools/ui_element_delegate.h"
+#include "ash/wm_window.h"
+#include "ui/views/widget/widget.h"
+
+namespace ash {
+namespace devtools {
+
+ViewElement::ViewElement(views::View* view,
+                         UIElementDelegate* ui_element_delegate,
+                         UIElement* parent)
+    : UIElement(UIElementType::VIEW, ui_element_delegate, parent), view_(view) {
+  if (!view_->HasObserver(this))
+    view_->AddObserver(this);
+}
+
+ViewElement::~ViewElement() {
+  if (view_ && view_->HasObserver(this))
+    view_->RemoveObserver(this);
+}
+
+views::View* ViewElement::view() {
+  return view_;
+}
+
+void ViewElement::OnChildViewRemoved(views::View* parent, views::View* view) {
+  if (parent == view_) {
+    for (auto* child_element : GetChildren()) {
+      if (UIElement::GetBackingElement<views::View, ViewElement>(
+              child_element) == view)
+        GetUIElementDelegate()->OnUIElementRemoved(child_element->GetNodeId());
+    }
+  }
+}
+
+void ViewElement::OnChildViewAdded(views::View* parent, views::View* view) {
+  if (parent == view_) {
+    GetUIElementDelegate()->OnUIElementAdded(
+        GetNodeId(), new ViewElement(view, GetUIElementDelegate(), this),
+        GetChildren().end() - 1);
+  }
+}
+
+void ViewElement::OnChildViewReordered(views::View* parent, views::View* view) {
+  if (view == view_) {
+    std::vector<UIElement*>::iterator prev_sibling_position =
+        GetUIElementDelegate()->OnUIElementRemoved(GetNodeId());
+
+    GetUIElementDelegate()->OnUIElementAdded(
+        GetParent()->GetNodeId(),
+        new ViewElement(view, GetUIElementDelegate(), GetParent()),

[sadrul, 2017/04/24 18:35:21]

This means there's a second ViewElement being created for |view|, right? (since
'this' also is for |view|) We need to avoid that, right?

... although, maybe in the OnUIElementRemoved() call above, |this| is destroyed,
and so we will still end up with a single ViewElement corresponding to |view|?
But, in that case, the GetUIElementDelegate() etc. calls in this line is causing
a use-after-free.

[thanhph, 2017/04/26 13:50:38]

This was the cause. I move Destroy() out of OnUIElementRemoved(). Thanks!

+        prev_sibling_position);
+  }

[sadrul, 2017/04/24 18:35:22]

When stacking/ordering changes, instead of 'remove' + 'add', can we just
introduce a OnUIElementReordered() or something like that to delegate? That
would simplify this quite a lot.

[thanhph, 2017/04/26 13:50:38]

I just call OnUIElementRemoved() and follow OnUIElementAdded() since these 2
functions are already implemented. The function RemoveChild() keeps track of the
prev_sibling_location instead of leaving it for OnUIElementRemoved() like
previous patches.

+}
+
+void ViewElement::OnViewBoundsChanged(views::View* view) {
+  if (view_ == view)
+    GetUIElementDelegate()->OnUIElementBoundsChanged(GetNodeId());
+}
+
+void ViewElement::Destroy() {
+  delete this;
+}
+
+bool ViewElement::GetBounds(gfx::Rect* bounds) {
+  if (view_) {
+    *bounds = view_->bounds();
+    return true;
+  }
+  return false;
+}
+
+bool ViewElement::SetBounds(const gfx::Rect& bounds) {
+  if (view_) {
+    view_->SetBoundsRect(bounds);
+    return true;
+  }
+  return false;
+}
+
+bool ViewElement::GetVisible(bool* visible) {
+  if (view_) {
+    *visible = view_->visible();
+    return true;
+  }
+  return false;
+}
+
+bool ViewElement::SetVisible(bool visible) {
+  if (view_) {
+    if (visible != view_->visible())
+      view_->SetVisible(visible);
+    return true;
+  }
+  return false;
+}
+
+std::pair<aura::Window*, gfx::Rect> ViewElement::GetNodeWindowAndBounds() {
+  if (view_)
+    return std::make_pair(view_->GetWidget()->GetNativeWindow(),
+                          view_->bounds());
+  return std::make_pair(nullptr, gfx::Rect());
+}
+
+// static
+views::View* ViewElement::From(UIElement* element) {
+  DCHECK_EQ(UIElementType::VIEW, element->GetType());
+  return static_cast<ViewElement*>(element)->view_;
+}
+
+}  // namespace devtools
+}  // namespace ash