ambient: show media string based on user pref.

We should keep the same user policy as lock-screen media controls:
namely, the ambient media string should only be available on lock-screen
when the corresponding pref has been enabled.

Bug: b/167488694.
Test: unittested.
Change-Id: I26256f1160ab869054fa18ec4360ab2cfd6f1815
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2380143
Commit-Queue: Meilin Wang <meilinw@chromium.org>
Reviewed-by: Xiaohui Chen <xiaohuic@chromium.org>
Reviewed-by: Tao Wu <wutao@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#804114}

ash/ambient/ui/media_string_view.cc

@@ -9,10 +9,13 @@
 
 #include "ash/ambient/util/ambient_util.h"
 #include "ash/assistant/ui/assistant_view_ids.h"
+#include "ash/public/cpp/ash_pref_names.h"
+#include "ash/session/session_controller_impl.h"
 #include "ash/shell.h"
 #include "ash/shell_delegate.h"
 #include "base/strings/string16.h"
 #include "base/strings/utf_string_conversions.h"
+#include "components/prefs/pref_service.h"
 #include "services/media_session/public/mojom/media_session.mojom.h"
 #include "services/media_session/public/mojom/media_session_service.mojom.h"
 #include "third_party/skia/include/core/SkColor.h"
@@ -30,6 +33,18 @@ constexpr char kPreceedingEighthNoteSymbol[] = "\u266A ";
 constexpr int kDefaultFontSizeDip = 64;
 constexpr int kMediaStringFontSizeDip = 16;
 
+// Returns true if we should show media string for ambient mode on lock-screen
+// based on user pref. We should keep the same user policy here as the
+// lock-screen media controls to avoid exposing user data on lock-screen without
+// consent.
+bool ShouldShowOnLockScreen() {
+  PrefService* pref =
+      Shell::Get()->session_controller()->GetPrimaryUserPrefService();
+  DCHECK(pref);
+
+  return pref->GetBoolean(prefs::kLockScreenMediaControlsEnabled);
+}
+
 }  // namespace
 
 MediaStringView::MediaStringView() {
@@ -45,6 +60,11 @@ const char* MediaStringView::GetClassName() const {
 
 void MediaStringView::MediaSessionInfoChanged(
     media_session::mojom::MediaSessionInfoPtr session_info) {
+  if (ambient::util::IsShowing(LockScreen::ScreenType::kLock) &&
+      !ShouldShowOnLockScreen()) {
+    return;
+  }
+
   // Don't show the media string if session info is unavailable, or the active
   // session is marked as sensitive.
   if (!session_info || session_info->is_sensitive) {

ash/ambient/ui/media_string_view_unittest.cc

@@ -5,13 +5,25 @@
 #include "ash/ambient/ui/media_string_view.h"
 
 #include "ash/ambient/test/ambient_ash_test_base.h"
+#include "ash/public/cpp/ash_pref_names.h"
+#include "ash/shell.h"
 #include "base/strings/string16.h"
 #include "base/strings/utf_string_conversions.h"
 #include "services/media_session/public/mojom/media_session.mojom.h"
 
 namespace ash {
 
-using MediaStringViewTest = AmbientAshTestBase;
+class MediaStringViewTest : public AmbientAshTestBase {
+ public:
+  MediaStringViewTest() : AmbientAshTestBase() {}
+  ~MediaStringViewTest() override = default;
+
+  // AmbientAshTestBase:
+  void SetUp() override {
+    AmbientAshTestBase::SetUp();
+    GetSessionControllerClient()->set_show_lock_screen_views(true);
+  }
+};
 
 TEST_F(MediaStringViewTest, ShowMediaTitleAndArtist) {
   ShowAmbientScreen();
@@ -53,4 +65,22 @@ TEST_F(MediaStringViewTest, DoNotShowWhenMediaIsPaused) {
   EXPECT_FALSE(GetMediaStringView()->GetVisible());
 }
 
+TEST_F(MediaStringViewTest, DoNotShowOnLockScreenIfPrefIsDisabled) {
+  // Disables user preference for media controls.
+  PrefService* pref =
+      Shell::Get()->session_controller()->GetPrimaryUserPrefService();
+  pref->SetBoolean(prefs::kLockScreenMediaControlsEnabled, false);
+
+  // Simulates Ambient Mode shown on lock-screen.
+  LockScreen();
+  FastForwardToInactivity();
+
+  // Simulates active and playing media session.
+  SimulateMediaPlaybackStateChanged(
+      media_session::mojom::MediaPlaybackState::kPlaying);
+
+  // Verifies media string is hidden.
+  EXPECT_FALSE(GetMediaStringView()->GetVisible());
+}
+
 }  // namespace ash