Couple of fixes for DesktopWindowTreeHostMus.

ui/views/mus/desktop_window_tree_host_mus.cc

 // Copyright 2016 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/mus/desktop_window_tree_host_mus.h"
 
 #include "base/memory/ptr_util.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/client/drag_drop_client.h"
 #include "ui/aura/client/focus_client.h"
@@ skipping 28 matching lines @@
   aura::Env::GetInstance()->RemoveObserver(this);
   desktop_native_widget_aura_->OnDesktopWindowTreeHostDestroyed(this);
 }
 
 bool DesktopWindowTreeHostMus::IsDocked() const {
   return window()->GetProperty(aura::client::kShowStateKey) ==
          ui::SHOW_STATE_DOCKED;
 }
 
 void DesktopWindowTreeHostMus::Init(aura::Window* content_window,
-                                    const Widget::InitParams& params) {}
+                                    const Widget::InitParams& params) {
+  // TODO: handle device scale, http://crbug.com/663524.
+  if (!params.bounds.IsEmpty())
+    SetBounds(params.bounds);
+}
 
 void DesktopWindowTreeHostMus::OnNativeWidgetCreated(
     const Widget::InitParams& params) {
   if (params.parent && params.parent->GetHost()) {
     parent_ = static_cast<DesktopWindowTreeHostMus*>(params.parent->GetHost());
     parent_->children_.insert(this);
   }
   native_widget_delegate_->OnNativeWidgetCreated(true);
 }
 
@@ skipping 43 matching lines @@
 }
 
 void DesktopWindowTreeHostMus::ShowWindowWithState(ui::WindowShowState state) {
   if (state == ui::SHOW_STATE_MAXIMIZED || state == ui::SHOW_STATE_FULLSCREEN ||
       state == ui::SHOW_STATE_DOCKED) {
     window()->SetProperty(aura::client::kShowStateKey, state);
   }
   window()->Show();
   if (compositor())
     compositor()->SetVisible(true);
-  // TODO: likely needs code to activate, but after content_window_ is shown.
-  // See NativeWidgetAura::ShowWithWindowState().
+
+  native_widget_delegate_->AsWidget()->SetInitialFocus(state);

[msw, 2016/11/10 18:27:45]

q: Should this check if native_widget_delgate_->CanActivate like
NativeWidgetMus? Also, do we care about the return value like NativeWidgetAura?
"Returns true if the initial focus has been set or the window should not set the
initial focus, or false if the caller should set the initial focus (if any)."

[sky, 2016/11/10 20:18:11]

I'm not exactly sure. That doesn't exist in the desktopwindowtreehost impls,
which seems weird. But I added it here for consistency.

 }
 
 void DesktopWindowTreeHostMus::ShowMaximizedWithBounds(
     const gfx::Rect& restored_bounds) {
   window()->SetProperty(aura::client::kRestoreBoundsKey,
                         new gfx::Rect(restored_bounds));
   ShowWindowWithState(ui::SHOW_STATE_MAXIMIZED);
 }
 
 bool DesktopWindowTreeHostMus::IsVisible() const {
@@ skipping 20 matching lines @@
   // TODO: implement window stacking, http://crbug.com/663617.
   NOTIMPLEMENTED();
 }
 
 void DesktopWindowTreeHostMus::StackAtTop() {
   // TODO: implement window stacking, http://crbug.com/663617.
   NOTIMPLEMENTED();
 }
 
 void DesktopWindowTreeHostMus::CenterWindow(const gfx::Size& size) {
-  NOTIMPLEMENTED();
+  gfx::Rect bounds_to_center_in = GetWorkAreaBoundsInScreen();
+
+  // If there is a transient parent and it fits |size|, then center over it.
+  aura::Window* content_window = desktop_native_widget_aura_->content_window();
+  if (wm::GetTransientParent(content_window)) {
+    gfx::Rect transient_parent_bounds =
+        wm::GetTransientParent(content_window)->GetBoundsInScreen();
+    if (transient_parent_bounds.height() >= size.height() &&
+        transient_parent_bounds.width() >= size.width()) {
+      bounds_to_center_in = transient_parent_bounds;
+    }
+  }
+
+  gfx::Rect resulting_bounds(

[msw, 2016/11/10 18:27:45]

Use gfx::Rect::ClampToCenteredSize, then skip AdjustToFit?

[sky, 2016/11/10 20:18:11]

Good call! Done.

+      bounds_to_center_in.x() +
+          (bounds_to_center_in.width() - size.width()) / 2,
+      bounds_to_center_in.y() +
+          (bounds_to_center_in.height() - size.height()) / 2,
+      size.width(), size.height());
+
+  // Don't size the window bigger than the parent, otherwise the user may not be
+  // able to close or move it.
+  resulting_bounds.AdjustToFit(bounds_to_center_in);
+
+  // TODO: handle device scale, http://crbug.com/663524. SetBounds() expects
+  // pixels.
+  SetBounds(resulting_bounds);
 }
 
 void DesktopWindowTreeHostMus::GetWindowPlacement(
     gfx::Rect* bounds,
     ui::WindowShowState* show_state) const {
   // Implementation matches that of NativeWidgetAura.
   *bounds = GetRestoredBounds();
   *show_state = window()->GetProperty(aura::client::kShowStateKey);
 }
 
@@ skipping 88 matching lines @@
   return window()->GetProperty(aura::client::kShowStateKey) ==
          ui::SHOW_STATE_MAXIMIZED;
 }
 
 bool DesktopWindowTreeHostMus::IsMinimized() const {
   return window()->GetProperty(aura::client::kShowStateKey) ==
          ui::SHOW_STATE_MINIMIZED;
 }
 
 bool DesktopWindowTreeHostMus::HasCapture() const {
-  return const_cast<aura::Window*>(window())->HasCapture();
+  // Capture state is held by DesktopNativeWidgetAura::content_window_.
+  // DesktopNativeWidgetAura::HasCapture() calls content_window_->HasCapture(),
+  // and this. That means this function can always return true.
+  return true;
 }
 
 void DesktopWindowTreeHostMus::SetAlwaysOnTop(bool always_on_top) {
   window()->SetProperty(aura::client::kAlwaysOnTopKey, always_on_top);
 }
 
 bool DesktopWindowTreeHostMus::IsAlwaysOnTop() const {
   return window()->GetProperty(aura::client::kAlwaysOnTopKey);
 }
 
@@ skipping 140 matching lines @@
   if (window == this->window()) {
     is_active_ = true;
     desktop_native_widget_aura_->HandleActivationChanged(true);
   } else if (is_active_) {
     is_active_ = false;
     desktop_native_widget_aura_->HandleActivationChanged(false);
   }
 }
 
 }  // namespace views