[Creation flow] Add a native back button to sign-in

This CL adds a native view toolbar on top of the Google sign-in page. So
far, this only contains a back button. A location bar will be added
in a follow-up CL.

The CL also extends the WidgetDelegate to be able to specify
ThemeProvider for the widget. This is needed because the profile picker
window exists without any Browser window as its parent widget and
native elements are used (and more of them will be used) that expect
existence of a ThemeProvider.

Bug: 1126913
Change-Id: I95286052338757619589bfbf1112acd06bd07fc1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2569752
Commit-Queue: Jan Krcal <jkrcal@chromium.org>
Reviewed-by: David Roger <droger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#841874}

chrome/browser/ui/views/profiles/profile_picker_view.cc

@@ -11,6 +11,7 @@
 #include "base/metrics/histogram_functions.h"
 #include "build/build_config.h"
 #include "chrome/app/chrome_command_ids.h"
+#include "chrome/app/vector_icons/vector_icons.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/extensions/chrome_extension_web_contents_observer.h"
 #include "chrome/browser/lifetime/application_lifetime.h"
@@ -22,11 +23,13 @@
 #include "chrome/browser/profiles/profiles_state.h"
 #include "chrome/browser/signin/identity_manager_factory.h"
 #include "chrome/browser/signin/signin_util.h"
+#include "chrome/browser/themes/theme_properties.h"
 #include "chrome/browser/themes/theme_service.h"
 #include "chrome/browser/themes/theme_service_factory.h"
 #include "chrome/browser/ui/browser_finder.h"
 #include "chrome/browser/ui/browser_navigator.h"
 #include "chrome/browser/ui/browser_navigator_params.h"
+#include "chrome/browser/ui/layout_constants.h"
 #include "chrome/browser/ui/user_manager.h"
 #include "chrome/browser/ui/views/accelerator_table.h"
 #include "chrome/browser/ui/views/frame/browser_view.h"
@@ -35,6 +38,7 @@
 #include "chrome/browser/ui/views/profiles/profile_customization_bubble_sync_controller.h"
 #include "chrome/browser/ui/views/profiles/profile_customization_bubble_view.h"
 #include "chrome/browser/ui/views/profiles/profile_picker_view_sync_delegate.h"
+#include "chrome/browser/ui/views/toolbar/toolbar_button.h"
 #include "chrome/browser/ui/webui/signin/dice_turn_sync_on_helper.h"
 #include "chrome/browser/ui/webui/signin/profile_picker_ui.h"
 #include "chrome/browser/ui/webui/signin/signin_web_dialog_ui.h"
@@ -42,11 +46,13 @@
 #include "chrome/common/pref_names.h"
 #include "chrome/common/webui_url_constants.h"
 #include "chrome/grit/chromium_strings.h"
+#include "chrome/grit/generated_resources.h"
 #include "chrome/grit/google_chrome_strings.h"
 #include "components/keep_alive_registry/keep_alive_types.h"
 #include "components/prefs/pref_service.h"
 #include "components/signin/public/identity_manager/account_info.h"
 #include "components/startup_metric_utils/browser/startup_metric_utils.h"
+#include "components/vector_icons/vector_icons.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/context_menu_params.h"
 #include "content/public/browser/render_frame_host.h"
@@ -54,6 +60,10 @@
 #include "content/public/browser/web_contents.h"
 #include "google_apis/gaia/gaia_urls.h"
 #include "net/base/url_util.h"
+#include "ui/base/l10n/l10n_util.h"
+#include "ui/views/accessibility/view_accessibility.h"
+#include "ui/views/background.h"
+#include "ui/views/controls/webview/web_contents_set_background_color.h"
 #include "ui/views/controls/webview/webview.h"
 #include "ui/views/layout/fill_layout.h"
 #include "ui/views/layout/flex_layout.h"
@@ -80,6 +90,9 @@ constexpr int kWindowWidth = 1024;
 constexpr int kWindowHeight = 758;
 constexpr float kMaxRatioOfWorkArea = 0.9;
 
+// Padding of elements in the simple toolbar.
+constexpr gfx::Insets kToolbarPadding = gfx::Insets(8);
+
 constexpr base::TimeDelta kExtendedAccountInfoTimeout =
     base::TimeDelta::FromSeconds(10);
 
@@ -153,6 +166,28 @@ class ProfilePickerWidget : public views::Widget {
   ProfilePickerView* const profile_picker_view_;
 };
 
+class SimpleBackButton : public ToolbarButton {
+ public:
+  explicit SimpleBackButton(PressedCallback callback)
+      : ToolbarButton(std::move(callback)) {
+    SetTriggerableEventFlags(ui::EF_LEFT_MOUSE_BUTTON |
+                             ui::EF_MIDDLE_MOUSE_BUTTON);
+    SetTooltipText(
+        l10n_util::GetStringUTF16(IDS_PROFILE_PICKER_BACK_BUTTON_LABEL));
+  }
+  SimpleBackButton(const SimpleBackButton&) = delete;
+  SimpleBackButton& operator=(const SimpleBackButton&) = delete;
+  ~SimpleBackButton() override = default;
+
+  // ToolbarButton:
+  void UpdateIcon() override {
+    const bool touch_ui = ui::TouchUiController::Get()->touch_ui();
+    const gfx::VectorIcon* image =
+        touch_ui ? &kBackArrowTouchIcon : &vector_icons::kBackArrowIcon;
+    UpdateIconsWithStandardColors(*image);
+  }
+};
+
 }  // namespace
 
 // static
@@ -367,6 +402,16 @@ void ProfilePickerView::SwitchToSignIn(
     base::OnceCallback<void(bool)> switch_finished_callback) {
   profile_color_ = profile_color;
 
+  if (signed_in_profile_being_created_) {
+    // The profile is already created (the user went back and forth again). No
+    // need to create it again.
+    std::move(switch_finished_callback).Run(true);
+    // Do not load any url because the desired sign-in screen is still loaded in
+    // `new_profile_contents_`.
+    ShowScreen(new_profile_contents_.get(), GURL(), /*show_toolbar=*/true);
+    return;
+  }
+
   DCHECK(!switch_finished_callback_);
   switch_finished_callback_ = std::move(switch_finished_callback);
 
@@ -404,6 +449,10 @@ void ProfilePickerView::OnProfileForSigninCreated(
     return;
   }
 
+  // Apply the default theme to get consistent colors for toolbars (this matters
+  // for linux where the 'system' theme is used for new profiles).
+  auto* theme_service = ThemeServiceFactory::GetForProfile(profile);
+  theme_service->UseDefaultTheme();
   if (signin_util::IsForceSigninEnabled()) {
     // Show the embedded sign-in flow if the force signin is enabled.
     UserManagerProfileDialog::ShowForceSigninDialog(
@@ -436,12 +485,28 @@ void ProfilePickerView::OnProfileForSigninCreated(
   // make sure the flow does not create multiple profiles simultaneously.
   signed_in_profile_being_created_ = profile;
 
-  // TODO(crbug.com/1126913): Build the simple toolbar with the back button.
+  // Build the toolbar. Do it as late as here because the elements depend on the
+  // ThemeProvider which is available only by signed_in_profile_being_created_.
+  const ui::ThemeProvider* tp = GetThemeProviderForProfileBeingCreated();
+  toolbar_->SetBackground(views::CreateSolidBackground(
+      tp->GetColor(ThemeProperties::COLOR_TOOLBAR)));
+
+  auto back_button = std::make_unique<SimpleBackButton>(base::BindRepeating(
+      &ProfilePickerView::BackButtonPressed, base::Unretained(this)));
+  toolbar_->AddChildView(std::move(back_button));
+
+  // TODO(crbug.com/1126913): Build the read-only omnibox.
 
   new_profile_contents_ = content::WebContents::Create(
       content::WebContents::CreateParams(signed_in_profile_being_created_));
   new_profile_contents_->SetDelegate(this);
 
+  // Make sure the web contents used for sign-in has proper background (for dark
+  // mode).
+  views::WebContentsSetBackgroundColor::CreateForWebContentsWithColor(
+      new_profile_contents_.get(),
+      tp->GetColor(ThemeProperties::COLOR_NTP_BACKGROUND));
+
   ShowScreen(new_profile_contents_.get(), GetSigninURL(),
              /*show_toolbar=*/true);
 }
@@ -578,6 +643,11 @@ void ProfilePickerView::BuildLayout() {
                                    views::MaximumFlexSizeRule::kUnbounded));
 
   auto toolbar = std::make_unique<views::View>();
+  toolbar->SetLayoutManager(std::make_unique<views::FlexLayout>())
+      ->SetOrientation(views::LayoutOrientation::kHorizontal)
+      .SetCrossAxisAlignment(views::LayoutAlignment::kCenter)
+      .SetCollapseMargins(true)
+      .SetInteriorMargin(kToolbarPadding);
   toolbar->SetProperty(
       views::kFlexBehaviorKey,
       views::FlexSpecification(views::MinimumFlexSizeRule::kPreferred,
@@ -592,9 +662,11 @@ void ProfilePickerView::BuildLayout() {
 void ProfilePickerView::ShowScreen(content::WebContents* contents,
                                    const GURL& url,
                                    bool show_toolbar) {
-  contents->GetController().LoadURL(url, content::Referrer(),
-                                    ui::PAGE_TRANSITION_AUTO_TOPLEVEL,
-                                    std::string());
+  if (!url.is_empty()) {
+    contents->GetController().LoadURL(url, content::Referrer(),
+                                      ui::PAGE_TRANSITION_AUTO_TOPLEVEL,
+                                      std::string());
+  }
   web_view_->SetWebContents(contents);
   web_view_->RequestFocus();
 
@@ -603,6 +675,22 @@ void ProfilePickerView::ShowScreen(content::WebContents* contents,
   toolbar_->SetVisible(show_toolbar);
 }
 
+void ProfilePickerView::BackButtonPressed(const ui::Event& event) {
+  if (web_view_->GetWebContents() != new_profile_contents_.get()) {
+    return;
+  }
+
+  if (new_profile_contents_->GetController().CanGoBack()) {
+    new_profile_contents_->GetController().GoBack();
+    return;
+  }
+
+  // Move from sign-in back to the previous screen of profile creation.
+  // Do not load any url because the desired screen is still loaded in
+  // `system_profile_contents_`.
+  ShowScreen(system_profile_contents_.get(), GURL(), /*show_toolbar=*/false);
+}
+
 void ProfilePickerView::OnRefreshTokenUpdatedForAccount(
     const CoreAccountInfo& account_info) {
   DCHECK(!account_info.IsEmpty());

chrome/browser/ui/views/profiles/profile_picker_view.h

@@ -108,11 +108,14 @@ class ProfilePickerView : public views::WidgetDelegateView,
   // Builds the views hieararchy.
   void BuildLayout();
 
-  // Shows a screen with `url` in `contents` and potentially `show_toolbar`.
+  // Shows a screen with `url` in `contents` and potentially `show_toolbar`. If
+  // `url` is empty, it only shows `contents` with its currently loaded url.
   void ShowScreen(content::WebContents* contents,
                   const GURL& url,
                   bool show_toolbar);
 
+  void BackButtonPressed(const ui::Event& event);
+
   // Helper functions to deal with the lack of extended account info.
   void SetExtendedAccountInfoTimeoutForTesting(base::TimeDelta timeout);
   void OnExtendedAccountInfoTimeout(const CoreAccountInfo& account);