Allow views_example with target_os="chromeos"

This CL introduces specific views_delegate implementation and
screen, a window tree host, and some aura clients to make the
views_examples working with target_os="chromeos".

Bug: 1106480
Test: manually checking views_examples
Change-Id: I25a8fc26d35e91452bd1bcee98f4b3bcecbd5021
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2304098
Commit-Queue: Jun Mukai <mukai@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Allen Bauer <kylixrd@chromium.org>
Cr-Commit-Position: refs/heads/master@{#789967}

ui/views/examples/BUILD.gn

@@ -169,6 +169,13 @@ source_set("views_examples_proc") {
   if (use_x11) {
     deps += [ "//ui/gfx/x" ]
   }
+  if (is_chromeos) {
+    sources += [
+      "examples_views_delegate_chromeos.cc",
+      "examples_views_delegate_chromeos.h",
+    ]
+    deps += [ "//ui/wm:test_support" ]
+  }
 }
 
 executable("views_examples") {

ui/views/examples/DEPS

@@ -11,3 +11,12 @@ include_rules = [
   "+ui/snapshot", # Enable Skia Gold testing
   "+ui/views_content_client",
 ]
+
+specific_include_rules = {
+  "examples_main_proc.cc": [
+    "+ui/wm/core/wm_state.h",
+  ],
+  "examples_views_delegate_chromeos.cc": [
+    "+ui/wm/test/wm_test_helper.h",
+  ],
+}

ui/views/examples/examples_main_proc.cc

@@ -52,6 +52,10 @@
 #include "ui/wm/core/wm_state.h"
 #endif
 
+#if defined(OS_CHROMEOS)
+#include "ui/views/examples/examples_views_delegate_chromeos.h"
+#endif
+
 #if BUILDFLAG(ENABLE_DESKTOP_AURA)
 #include "ui/views/widget/desktop_aura/desktop_screen.h"
 #endif
@@ -154,10 +158,14 @@ ExamplesExitCode ExamplesMainProc(bool under_test) {
   ExamplesExitCode compare_result = ExamplesExitCode::kSucceeded;
 
   {
+#if defined(OS_CHROMEOS)
+    ExamplesViewsDelegateChromeOS views_delegate;
+#else
     views::DesktopTestViewsDelegate views_delegate;
 #if defined(USE_AURA)
     wm::WMState wm_state;
 #endif
+#endif
 #if BUILDFLAG(ENABLE_DESKTOP_AURA)
     std::unique_ptr<display::Screen> desktop_screen =
         base::WrapUnique(views::CreateDesktopScreen());

ui/views/examples/examples_views_delegate_chromeos.cc

+// Copyright (c) 2020 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/examples/examples_views_delegate_chromeos.h"
+
+#include "ui/views/examples/examples_window.h"
+#include "ui/wm/test/wm_test_helper.h"
+
+namespace views {
+namespace examples {
+
+namespace {
+constexpr gfx::Size kDefaultSize(1024, 768);
+}  // namespace
+
+ExamplesViewsDelegateChromeOS::ExamplesViewsDelegateChromeOS()
+    : observer_(this) {}
+
+ExamplesViewsDelegateChromeOS::~ExamplesViewsDelegateChromeOS() = default;
+
+void ExamplesViewsDelegateChromeOS::OnBeforeWidgetInit(
+    Widget::InitParams* params,
+    internal::NativeWidgetDelegate* delegate) {
+  views::TestViewsDelegate::OnBeforeWidgetInit(params, delegate);
+  if (!params->parent && !params->context) {
+    DCHECK(!wm_helper_);
+
+    wm_helper_ = std::make_unique<wm::WMTestHelper>(kDefaultSize);
+    wm_helper_->host()->Show();
+    observer_.Add(wm_helper_->host());
+    params->context = wm_helper_->host()->window();
+  }
+}
+
+void ExamplesViewsDelegateChromeOS::OnHostCloseRequested(
+    aura::WindowTreeHost* host) {
+  Widget* widget = GetExamplesWidget();
+  if (widget) {
+    observer_.Remove(host);
+    widget->Close();
+  }
+}
+
+}  // namespace examples
+}  // namespace views

ui/views/examples/examples_views_delegate_chromeos.h

+// Copyright (c) 2020 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.
+
+#ifndef UI_VIEWS_EXAMPLES_EXAMPLES_VIEWS_DELEGATE_CHROMEOS_H_
+#define UI_VIEWS_EXAMPLES_EXAMPLES_VIEWS_DELEGATE_CHROMEOS_H_
+
+#include <memory>
+
+#include "base/scoped_observer.h"
+#include "ui/aura/window_tree_host.h"
+#include "ui/aura/window_tree_host_observer.h"
+#include "ui/views/test/desktop_test_views_delegate.h"
+
+namespace wm {
+class WMTestHelper;
+}
+
+namespace views {
+namespace examples {
+
+class ExamplesViewsDelegateChromeOS : public DesktopTestViewsDelegate,
+                                      public aura::WindowTreeHostObserver {
+ public:
+  ExamplesViewsDelegateChromeOS();
+  ~ExamplesViewsDelegateChromeOS() override;
+
+ private:
+  // ViewsDelegate:
+  void OnBeforeWidgetInit(Widget::InitParams* params,
+                          internal::NativeWidgetDelegate* delegate) override;
+
+  // aura::WindowTreeHostObserver:
+  void OnHostCloseRequested(aura::WindowTreeHost* host) override;
+
+  ScopedObserver<aura::WindowTreeHost, aura::WindowTreeHostObserver> observer_;
+  std::unique_ptr<wm::WMTestHelper> wm_helper_;
+};
+
+}  // namespace examples
+}  // namespace views
+
+#endif  // UI_VIEWS_EXAMPLES_EXAMPLES_VIEWS_DELEGATE_CHROMEOS_H_

ui/views/examples/examples_window.cc

@@ -207,6 +207,12 @@ class ExamplesWindowContents : public WidgetDelegateView,
 // static
 ExamplesWindowContents* ExamplesWindowContents::instance_ = nullptr;
 
+Widget* GetExamplesWidget() {
+  return ExamplesWindowContents::instance()
+             ? ExamplesWindowContents::instance()->GetWidget()
+             : nullptr;
+}
+
 void ShowExamplesWindow(base::OnceClosure on_close,
                         ExampleVector examples,
                         gfx::NativeWindow window_context) {

ui/views/examples/examples_window.h

@@ -17,10 +17,15 @@
 #include "ui/views/examples/views_examples_export.h"
 
 namespace views {
+class Widget;
+
 namespace examples {
 
 VIEWS_EXAMPLES_EXPORT extern const char kExamplesWidgetName[];
 
+// Returns the current widget.
+VIEWS_EXAMPLES_EXPORT Widget* GetExamplesWidget();
+
 // Shows a window with the views examples in it. |extra_examples| contains any
 // additional examples to add. |window_context| is used to determine where the
 // window should be created (see |Widget::InitParams::context| for details).

ui/views_content_client/views_content_client_main_parts_aura.cc

@@ -20,7 +20,9 @@ ViewsContentClientMainPartsAura::~ViewsContentClientMainPartsAura() {
 void ViewsContentClientMainPartsAura::ToolkitInitialized() {
   ViewsContentClientMainParts::ToolkitInitialized();
 
+#if !defined(OS_CHROMEOS)
   wm_state_ = std::make_unique<::wm::WMState>();
+#endif
 }
 
 void ViewsContentClientMainPartsAura::PostMainMessageLoopRun() {

ui/views_content_client/views_content_client_main_parts_chromeos.cc

@@ -43,7 +43,7 @@ void ViewsContentClientMainPartsChromeOS::PreMainMessageLoopRun() {
   ViewsContentClientMainPartsAura::PreMainMessageLoopRun();
 
   // Set up basic pieces of views::corewm.
-  wm_test_helper_ = std::make_unique<wm::WMTestHelper>(gfx::Size(800, 600));
+  wm_test_helper_ = std::make_unique<wm::WMTestHelper>(gfx::Size(1024, 768));
   // Ensure the X window gets mapped.
   wm_test_helper_->host()->Show();