Separate test logic from aura and provide production implementation (#6976)

This PR extracts test-specific logic from Aura by guarding them under
`RUN_BROWSER_TESTS` preprocessor, and provides production logics for the
production conditions.
This PR also removes `testonly` flag from group("cobalt_shell_lib_deps")
, and put all test dependencies to source_set("browsertests_sources")
after the last remaining test-specific logic is separated from Aura.

Test: as Aura is only used in Linux, I built and ran CUJ on linux debug
and linux gold.
Bug: 437981348

Author: haozheng-cobalt

cobalt/shell/BUILD.gn

@@ -43,11 +43,7 @@ source_set("android_shell_descriptors") {
 }
 
 group("cobalt_shell_lib_deps") {
-  testonly = true
-  visibility = [
-    "//cobalt/shell:*",
-    "//cobalt/testing:*",
-  ]
+  visibility = [ "//cobalt/shell:*" ]
 
   public_deps = [
     ":android_shell_descriptors",
@@ -131,7 +127,6 @@ group("cobalt_shell_lib_deps") {
   if (use_aura) {
     public_deps += [
       "//ui/aura",
-      "//ui/aura:test_support",
       "//ui/events",
       "//ui/wm",
     ]
@@ -141,9 +136,7 @@ group("cobalt_shell_lib_deps") {
         "//ui/color:color_headers",
         "//ui/native_theme",
         "//ui/resources",
-        "//ui/views:test_support",
         "//ui/views/controls/webview",
-        "//ui/wm:test_support",
       ]
     }
   }
@@ -201,6 +194,17 @@ source_set("browsertests_sources") {
     "//services/test/echo:lib",
     "//services/test/echo/public/mojom",
   ]
+
+  if (use_aura) {
+    public_deps += [ "//ui/aura:test_support" ]
+
+    if (shell_use_toolkit_views) {
+      public_deps += [
+        "//ui/views:test_support",
+        "//ui/wm:test_support",
+      ]
+    }
+  }
 }
 
 static_library("cobalt_shell_lib") {
@@ -302,6 +306,8 @@ static_library("cobalt_shell_lib") {
   if (use_aura) {
     if (shell_use_toolkit_views) {
       sources += [
+        "browser/cobalt_views_delegate.cc",
+        "browser/cobalt_views_delegate.h",
         "browser/shell_platform_delegate_views.cc",
         "browser/shell_web_contents_view_delegate_views.cc",
       ]

cobalt/shell/browser/cobalt_views_delegate.cc

@@ -0,0 +1,50 @@
+// Copyright 2025 The Cobalt Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "cobalt/shell/browser/cobalt_views_delegate.h"
+
+#include "build/build_config.h"
+#include "ui/views/buildflags.h"
+#include "ui/views/widget/native_widget_aura.h"
+
+#if BUILDFLAG(ENABLE_DESKTOP_AURA)
+#include "ui/views/widget/desktop_aura/desktop_native_widget_aura.h"
+#endif
+
+namespace views {
+
+CobaltViewsDelegate::CobaltViewsDelegate() = default;
+
+CobaltViewsDelegate::~CobaltViewsDelegate() = default;
+
+void CobaltViewsDelegate::OnBeforeWidgetInit(
+    Widget::InitParams* params,
+    internal::NativeWidgetDelegate* delegate) {
+#if BUILDFLAG(ENABLE_DESKTOP_AURA)
+  // If we already have a native_widget, we don't have to try to come
+  // up with one.
+  if (params->native_widget) {
+    return;
+  }
+
+  if (params->parent && params->type != views::Widget::InitParams::TYPE_MENU &&
+      params->type != views::Widget::InitParams::TYPE_TOOLTIP) {
+    params->native_widget = new views::NativeWidgetAura(delegate);
+  } else {
+    params->native_widget = new views::DesktopNativeWidgetAura(delegate);
+  }
+#endif
+}
+
+}  // namespace views

cobalt/shell/browser/cobalt_views_delegate.h

@@ -0,0 +1,42 @@
+// Copyright 2025 The Cobalt Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef COBALT_SHELL_BROWSER_COBALT_VIEWS_DELEGATE_H_
+#define COBALT_SHELL_BROWSER_COBALT_VIEWS_DELEGATE_H_
+
+#include <memory>
+
+#include "base/memory/raw_ptr.h"
+#include "build/build_config.h"
+#include "ui/views/layout/layout_provider.h"
+#include "ui/views/views_delegate.h"
+
+namespace views {
+
+class CobaltViewsDelegate : public ViewsDelegate {
+ public:
+  CobaltViewsDelegate();
+
+  CobaltViewsDelegate(const CobaltViewsDelegate&) = delete;
+  CobaltViewsDelegate& operator=(const CobaltViewsDelegate&) = delete;
+
+  ~CobaltViewsDelegate() override;
+
+  void OnBeforeWidgetInit(Widget::InitParams* params,
+                          internal::NativeWidgetDelegate* delegate) override;
+};
+
+}  // namespace views
+
+#endif  // COBALT_SHELL_BROWSER_COBALT_VIEWS_DELEGATE_H_

cobalt/shell/browser/shell_platform_data_aura.cc

@@ -19,25 +19,31 @@
 #include "base/memory/raw_ptr.h"
 #include "build/build_config.h"
 #include "cobalt/shell/browser/shell.h"
-#include "ui/aura/client/cursor_shape_client.h"
 #include "ui/aura/client/default_capture_client.h"
 #include "ui/aura/env.h"
 #include "ui/aura/layout_manager.h"
-#include "ui/aura/test/test_focus_client.h"
-#include "ui/aura/test/test_window_parenting_client.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_event_dispatcher.h"
 #include "ui/base/ime/init/input_method_factory.h"
 #include "ui/base/ime/input_method.h"
 #include "ui/ozone/public/ozone_platform.h"
 #include "ui/platform_window/platform_window_init_properties.h"
-#include "ui/wm/core/cursor_loader.h"
 #include "ui/wm/core/default_activation_client.h"
 
 #if BUILDFLAG(IS_OZONE)
 #include "ui/aura/screen_ozone.h"
 #endif
 
+#if defined(RUN_BROWSER_TESTS)
+#include "ui/aura/client/cursor_shape_client.h"         // nogncheck
+#include "ui/aura/test/test_focus_client.h"             // nogncheck
+#include "ui/aura/test/test_window_parenting_client.h"  // nogncheck
+#include "ui/wm/core/cursor_loader.h"                   // nogncheck
+#else
+#include "ui/wm/core/base_focus_rules.h"
+#include "ui/wm/core/focus_controller.h"
+#endif  // defined(RUN_BROWSER_TESTS)
+
 namespace content {
 
 namespace {
@@ -85,6 +91,22 @@ class FillLayout : public aura::LayoutManager {
   bool has_bounds_;
 };
 
+#if !defined(RUN_BROWSER_TESTS)
+class FocusRules : public wm::BaseFocusRules {
+ public:
+  FocusRules() = default;
+  FocusRules(const FocusRules&) = delete;
+  FocusRules& operator=(const FocusRules&) = delete;
+  ~FocusRules() override = default;
+
+ private:
+  // wm::BaseFocusRules:
+  bool SupportsChildActivation(const aura::Window* window) const override {
+    return true;
+  }
+};
+#endif  // !defined(RUN_BROWSER_TESTS)
+
 }  // namespace
 
 ShellPlatformDataAura::ShellPlatformDataAura(const gfx::Size& initial_size) {
@@ -104,20 +126,30 @@ ShellPlatformDataAura::ShellPlatformDataAura(const gfx::Size& initial_size) {
   host_->window()->SetLayoutManager(
       std::make_unique<FillLayout>(host_->window()));
 
+#if defined(RUN_BROWSER_TESTS)
   focus_client_ =
       std::make_unique<aura::test::TestFocusClient>(host_->window());
 
   new wm::DefaultActivationClient(host_->window());
+#else
+  // Reference void AuraContext::InitializeWindowTreeHost(aura::WindowTreeHost*
+  // host) from ui/webui/examples/browser/ui/aura/aura_context.cc
+  focus_client_ = std::make_unique<wm::FocusController>(new FocusRules());
+  aura::client::SetFocusClient(host_->window(), focus_client_.get());
+#endif  // defined(RUN_BROWSER_TESTS)
+
   capture_client_ =
       std::make_unique<aura::client::DefaultCaptureClient>(host_->window());
+
+#if defined(RUN_BROWSER_TESTS)
   window_parenting_client_ =
       std::make_unique<aura::test::TestWindowParentingClient>(host_->window());
-
   // TODO(https://crbug.com/1336055): this is needed for
   // mouse_cursor_overlay_controller_browsertest.cc on cast_shell_linux as
   // currently, when is_castos = true, the views toolkit isn't used.
   cursor_shape_client_ = std::make_unique<wm::CursorLoader>();
   aura::client::SetCursorShapeClient(cursor_shape_client_.get());
+#endif  // defined(RUN_BROWSER_TESTS)
 }
 
 ShellPlatformDataAura::~ShellPlatformDataAura() {

cobalt/shell/browser/shell_platform_data_aura.h

@@ -22,10 +22,12 @@
 
 namespace aura {
 namespace client {
-class CursorShapeClient;
-class DefaultCaptureClient;
 class FocusClient;
+class DefaultCaptureClient;
+#if defined(RUN_BROWSER_TESTS)
+class CursorShapeClient;
 class WindowParentingClient;
+#endif  // defined(RUN_BROWSER_TESTS)
 }  // namespace client
 }  // namespace aura
 
@@ -63,8 +65,11 @@ class ShellPlatformDataAura {
   std::unique_ptr<aura::WindowTreeHost> host_;
   std::unique_ptr<aura::client::FocusClient> focus_client_;
   std::unique_ptr<aura::client::DefaultCaptureClient> capture_client_;
+
+#if defined(RUN_BROWSER_TESTS)
   std::unique_ptr<aura::client::WindowParentingClient> window_parenting_client_;
   std::unique_ptr<aura::client::CursorShapeClient> cursor_shape_client_;
+#endif  // defined(RUN_BROWSER_TESTS)
 };
 
 }  // namespace content

cobalt/shell/browser/shell_platform_delegate_views.cc

@@ -47,14 +47,19 @@
 #include "ui/views/layout/box_layout_view.h"
 #include "ui/views/layout/flex_layout_types.h"
 #include "ui/views/layout/flex_layout_view.h"
-#include "ui/views/test/desktop_test_views_delegate.h"
 #include "ui/views/view.h"
 #include "ui/views/view_class_properties.h"
 #include "ui/views/widget/desktop_aura/desktop_screen.h"
 #include "ui/views/widget/widget.h"
 #include "ui/views/widget/widget_delegate.h"
 #include "ui/wm/core/wm_state.h"
 
+#if defined(RUN_BROWSER_TESTS)
+#include "ui/views/test/desktop_test_views_delegate.h"  // nogncheck
+#else
+#include "cobalt/shell/browser/cobalt_views_delegate.h"
+#endif  // defined(RUN_BROWSER_TESTS)
+
 namespace content {
 
 struct ShellPlatformDelegate::ShellData {
@@ -318,8 +323,12 @@ void ShellPlatformDelegate::Initialize(const gfx::Size& default_window_size) {
     platform_->screen = views::CreateDesktopScreen();
   }
 
+#if defined(RUN_BROWSER_TESTS)
   platform_->views_delegate =
       std::make_unique<views::DesktopTestViewsDelegate>();
+#else
+  platform_->views_delegate = std::make_unique<views::CobaltViewsDelegate>();
+#endif  // defined(RUN_BROWSER_TESTS)
 }
 
 ShellPlatformDelegate::~ShellPlatformDelegate() = default;