capture_selfie_cam: Add a11y alert on preview visibility changes

Bug: 1302690
Change-Id: I9bdb8565c5adfc542e5cd6735e9911f735ed04eb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3523742
Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Commit-Queue: Min Chen <minch@chromium.org>
Cr-Commit-Position: refs/heads/main@{#986247}

ash/ash_strings.grd

@@ -4021,6 +4021,12 @@ Here are some things you can try to get started.
       <message name="IDS_ASH_SCREEN_CAPTURE_ALERT_RECORD_MICROPHONE_TOGGLE" desc="Alert spoken by screen readers when record microphone setting is toggled.">
         Record microphone <ph name="STATE">$1<ex>off</ex></ph>
       </message>
+      <message name="IDS_ASH_SCREEN_CAPTURE_CAMERA_PREVIEW_ON" desc="Alert spoken by screen readers when camera preview is shown.">
+        Camera preview on
+      </message>
+      <message name="IDS_ASH_SCREEN_CAPTURE_CAMERA_PREVIEW_HIDDEN" desc="Alert spoken by screen readers when camera preview is hidden.">
+        Camera preview hidden
+      </message>
       <message name="IDS_ASH_SCREEN_CAPTURE_NAVIGATION_ALERT_RECORD_MICROPHONE" desc="Alert spoken by screen readers when user tabs to record microphone setting.">
         Record microphone <ph name="CURRENT_STATE">$1<ex>off</ex></ph>, Press enter to turn microphone recording <ph name="NEW_STATE">$2<ex>on</ex></ph>
       </message>

ash/ash_strings_grd/IDS_ASH_SCREEN_CAPTURE_CAMERA_PREVIEW_HIDDEN.png.sha1

@@ -0,0 +1 @@
+9cabcf13e4330de451a4a5735b2af1504698f145

ash/ash_strings_grd/IDS_ASH_SCREEN_CAPTURE_CAMERA_PREVIEW_ON.png.sha1

@@ -0,0 +1 @@
+3e6fbfe2e347b80b74f31c080ebd3096d94a522a

ash/capture_mode/capture_mode_camera_controller.cc

@@ -11,9 +11,11 @@
 #include "ash/capture_mode/capture_mode_constants.h"
 #include "ash/capture_mode/capture_mode_controller.h"
 #include "ash/capture_mode/capture_mode_session.h"
+#include "ash/capture_mode/capture_mode_util.h"
 #include "ash/public/cpp/capture_mode/capture_mode_delegate.h"
 #include "ash/public/cpp/shell_window_ids.h"
 #include "ash/shell.h"
+#include "ash/strings/grit/ash_strings.h"
 #include "base/bind.h"
 #include "base/callback_helpers.h"
 #include "base/check.h"
@@ -266,8 +268,6 @@ void CaptureModeCameraController::SetSelectedCamera(CameraId camera_id) {
 
   selected_camera_ = std::move(camera_id);
   camera_reconnect_timer_.Stop();
-  camera_preview_widget_.reset();
-  camera_preview_view_ = nullptr;
 
   for (auto& observer : observers_)
     observer.OnSelectedCameraChanged(selected_camera_);
@@ -284,6 +284,7 @@ void CaptureModeCameraController::MaybeReparentPreviewWidget() {
   if (!camera_preview_widget_)
     return;
 
+  const bool was_visible_before = camera_preview_widget_->IsVisible();
   auto* controller = CaptureModeController::Get();
   DCHECK(!controller->is_recording_in_progress());
   auto* parent = controller->GetCameraPreviewParentWindow();
@@ -294,6 +295,11 @@ void CaptureModeCameraController::MaybeReparentPreviewWidget() {
     views::Widget::ReparentNativeView(native_window, parent);
 
   MaybeUpdatePreviewWidgetBounds();
+  if (was_visible_before != camera_preview_widget_->IsVisible()) {
+    capture_mode_util::TriggerAccessibilityAlert(
+        was_visible_before ? IDS_ASH_SCREEN_CAPTURE_CAMERA_PREVIEW_HIDDEN
+                           : IDS_ASH_SCREEN_CAPTURE_CAMERA_PREVIEW_ON);
+  }
 }
 
 void CaptureModeCameraController::SetCameraPreviewSnapPosition(
@@ -480,6 +486,12 @@ void CaptureModeCameraController::OnCameraDevicesReceived(
 }
 
 void CaptureModeCameraController::RefreshCameraPreview() {
+  const bool was_visible_before =
+      camera_preview_widget_ && camera_preview_widget_->IsVisible();
+  base::ScopedClosureRunner deferred_runner(base::BindOnce(
+      &CaptureModeCameraController::TriggerA11yAlertAfterCameraRefresh,
+      weak_ptr_factory_.GetWeakPtr(), was_visible_before));
+
   const CameraInfo* camera_info = nullptr;
   if (selected_camera_.is_valid()) {
     if (camera_info = GetCameraInfoById(selected_camera_, available_cameras_);
@@ -509,6 +521,14 @@ void CaptureModeCameraController::RefreshCameraPreview() {
     return;
   }
 
+  // Destroying the existing camera preview widget before recreating a new one
+  // when a different camera was selected.
+  if (camera_preview_view_ &&
+      camera_preview_view_->camera_id() != selected_camera_) {
+    camera_preview_widget_.reset();
+    camera_preview_view_ = nullptr;
+  }
+
   if (!camera_preview_widget_) {
     const auto preview_bounds = GetPreviewWidgetBounds();
     camera_preview_widget_ = CreateCameraPreviewWidget(preview_bounds);
@@ -617,4 +637,16 @@ gfx::Rect CaptureModeCameraController::
   return preview_window->bounds();
 }
 
+void CaptureModeCameraController::TriggerA11yAlertAfterCameraRefresh(
+    bool was_preview_visible_before) {
+  const bool is_preview_visible_now =
+      camera_preview_widget_ && camera_preview_widget_->IsVisible();
+  if (was_preview_visible_before != is_preview_visible_now) {
+    capture_mode_util::TriggerAccessibilityAlert(
+        was_preview_visible_before
+            ? IDS_ASH_SCREEN_CAPTURE_CAMERA_PREVIEW_HIDDEN
+            : IDS_ASH_SCREEN_CAPTURE_CAMERA_PREVIEW_ON);
+  }
+}
+
 }  // namespace ash

ash/capture_mode/capture_mode_camera_controller.h

@@ -243,6 +243,12 @@ class ASH_EXPORT CaptureModeCameraController
 
   void SetBoundsOnPreviewWidget(const gfx::Rect& bounds);
 
+  // Triggers a11y alert after RefreshCameraPreview() based on
+  // `was_preview_visible_before` and the current visibility of
+  // `camera_preview_widget_`. `was_preview_visible_before` is the visibility of
+  // the camera preview when RefreshCameraPreview() was called.
+  void TriggerA11yAlertAfterCameraRefresh(bool was_preview_visible_before);
+
   // Owned by CaptureModeController and guaranteed to be not null and to outlive
   // `this`.
   CaptureModeDelegate* const delegate_;