exo: Implement minimal support for version 6 of XDG shell.

components/exo/shell_surface.cc

 // Copyright 2015 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 "components/exo/shell_surface.h"
 
 #include <algorithm>
 
 #include "ash/aura/wm_window_aura.h"
 #include "ash/common/shelf/wm_shelf.h"
@@ skipping 619 matching lines @@
   return value;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // SurfaceDelegate overrides:
 
 void ShellSurface::OnSurfaceCommit() {
   surface_->CheckIfSurfaceHierarchyNeedsCommitToNewSurfaces();
   surface_->CommitSurfaceHierarchy();
 
-  if (enabled() && !widget_)
-    CreateShellSurfaceWidget(ui::SHOW_STATE_NORMAL);
+  if (enabled() && !widget_) {
+    // Defer widget creation until surface contains some contents.
+    if (surface_->content_size().IsEmpty())
+      Configure();
+    else
+      CreateShellSurfaceWidget(ui::SHOW_STATE_NORMAL);
+  }
 
   // Apply the accumulated pending origin offset to reflect acknowledged
   // configure requests.
   origin_ += pending_origin_offset_;
   pending_origin_offset_ = gfx::Vector2d();
 
   // Update resize direction to reflect acknowledged configure requests.
   resize_component_ = pending_resize_component_;
 
   if (widget_) {
@@ skipping 417 matching lines @@
       new CustomWindowStateDelegate(widget_)));
 
   // Receive accessibility changes to update shadow underlay.
   WMHelper::GetInstance()->AddAccessibilityObserver(this);
 
   // Show widget next time Commit() is called.
   pending_show_widget_ = true;
 }
 
 void ShellSurface::Configure() {
-  DCHECK(widget_);
-
   // Delay configure callback if |scoped_configure_| is set.
   if (scoped_configure_) {
     scoped_configure_->set_needs_configure();
     return;
   }
 
   gfx::Vector2d origin_offset = pending_origin_config_offset_;
   pending_origin_config_offset_ = gfx::Vector2d();
 
   // If surface is being resized, save the resize direction.
   int resize_component =
       resizer_ ? resizer_->details().window_component : HTCAPTION;
 
   if (configure_callback_.is_null()) {
     pending_origin_offset_ += origin_offset;
     pending_resize_component_ = resize_component;
     return;
   }
 
-  uint32_t serial = configure_callback_.Run(
-      widget_->GetWindowBoundsInScreen().size(),
-      ash::wm::GetWindowState(widget_->GetNativeWindow())->GetStateType(),
-      IsResizing(), widget_->IsActive());
+  uint32_t serial;
+  if (widget_) {

[Daniele Castagna, 2016/10/20 20:09:16]

Can you mention in the CL description why the widget_ can now be nullptr?

[reveman, 2017/01/30 22:54:05]

Done.

+    serial = configure_callback_.Run(
+        widget_->GetWindowBoundsInScreen().size(),
+        ash::wm::GetWindowState(widget_->GetNativeWindow())->GetStateType(),
+        IsResizing(), widget_->IsActive());
+  } else {
+    serial = configure_callback_.Run(
+        gfx::Size(), ash::wm::WINDOW_STATE_TYPE_NORMAL, false, false);
+  }
 
   // Apply origin offset and resize component at the first Commit() after this
   // configure request has been acknowledged.
   pending_configs_.push_back({serial, origin_offset, resize_component});
   LOG_IF(WARNING, pending_configs_.size() > 100)
       << "Number of pending configure acks for shell surface has reached: "
       << pending_configs_.size();
 }
 
 void ShellSurface::AttemptToStartDrag(int component) {
@@ skipping 277 matching lines @@
       shadow_overlay_->layer()->Add(shadow->layer());
       window->AddChild(shadow_overlay_);
       shadow_overlay_->Show();
     }
     shadow_overlay_->SetBounds(shadow_bounds);
     shadow->SetContentBounds(gfx::Rect(shadow_bounds.size()));
   }
 }
 
 }  // namespace exo