[fuchsia] Enforce AUDIO ContextFeatureFlag

Before using the audio service, check that the AUDIO feature flag is
enabled.

Test: WebEngineIntegrationTest.PlayAudio*
Bug: 1070571
Change-Id: I4f88887e24dd899748fa7959875b5c2b5753eee3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2365992
Reviewed-by: Sergey Ulanov <sergeyu@chromium.org>
Reviewed-by: Becca Hughes <beccahughes@chromium.org>
Reviewed-by: Wez <wez@chromium.org>
Reviewed-by: David Dorwin <ddorwin@chromium.org>
Commit-Queue: Sharon Yang <yangsharon@chromium.org>
Cr-Commit-Position: refs/heads/master@{#807189}

fuchsia/engine/browser/media_resource_provider_service.cc

@@ -19,6 +19,7 @@
 #include "content/public/browser/storage_partition.h"
 #include "fuchsia/engine/browser/frame_impl.h"
 #include "fuchsia/engine/switches.h"
+#include "media/base/media_switches.h"
 #include "media/base/provision_fetcher.h"
 #include "media/fuchsia/cdm/service/fuchsia_cdm_manager.h"
 #include "third_party/widevine/cdm/widevine_cdm_common.h"
@@ -81,6 +82,14 @@ void MediaResourceProviderImpl::CreateCdm(
 
 void MediaResourceProviderImpl::CreateAudioConsumer(
     fidl::InterfaceRequest<fuchsia::media::AudioConsumer> request) {
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kDisableAudioOutput)) {
+    LOG(WARNING)
+        << "Could not create AudioConsumer because audio output feature flag "
+           "was not enabled.";
+    return;
+  }
+
   auto factory = base::ComponentContextForProcess()
                      ->svc()
                      ->Connect<fuchsia::media::SessionAudioConsumerFactory>();
@@ -91,6 +100,14 @@ void MediaResourceProviderImpl::CreateAudioConsumer(
 
 void MediaResourceProviderImpl::CreateAudioCapturer(
     fidl::InterfaceRequest<fuchsia::media::AudioCapturer> request) {
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kDisableAudioInput)) {
+    LOG(WARNING)
+        << "Could not create AudioCapturer because audio input feature flag "
+           "was not enabled.";
+    return;
+  }
+
   if (FrameImpl::FromRenderFrameHost(render_frame_host())
           ->permission_controller()
           ->GetPermissionState(content::PermissionType::AUDIO_CAPTURE,

fuchsia/engine/context_provider_impl.cc

@@ -447,6 +447,15 @@ void ContextProviderImpl::Create(
                                       key_system);
   }
 
+  bool enable_audio = (features & fuchsia::web::ContextFeatureFlags::AUDIO) ==
+                      fuchsia::web::ContextFeatureFlags::AUDIO;
+  if (!enable_audio) {
+    // TODO(fxbug.dev/58902): Split up audio input and output in
+    // ContextFeatureFlags.
+    launch_command.AppendSwitch(switches::kDisableAudioOutput);
+    launch_command.AppendSwitch(switches::kDisableAudioInput);
+  }
+
   zx::channel cdm_data_directory_channel;
   if (enable_widevine || enable_playready) {
     DCHECK(params.has_cdm_data_directory());

fuchsia/engine/test/data/play_audio.html

@@ -6,6 +6,9 @@
       mediaSource = new MediaSource();
       audio.src = URL.createObjectURL(mediaSource);
 
+      audio.onended = function() { document.title = 'ended'; }
+      audio.onerror = function() { document.title = 'error'; }
+
       // Play two files with different sample rate to force mid-stream
       // re-initialization.
       var files = ["bear-44.1kHz.webm", "bear-48kHz.webm"];
@@ -40,7 +43,6 @@
       }
 
       audio.play();
-      audio.onended = function() { document.title = 'ended'; }
     </script>
   </body>
 </html>

fuchsia/engine/web_engine_integration_test.cc

@@ -128,14 +128,13 @@ class WebEngineIntegrationTest : public testing::Test {
     // service.
     fuchsia::web::CreateContextParams create_params =
         ContextParamsWithFilteredServiceDirectory();
+    create_params.set_features(fuchsia::web::ContextFeatureFlags::AUDIO);
 
     fake_audio_consumer_service_ =
         std::make_unique<media::FakeAudioConsumerService>(
             filtered_service_directory_->outgoing_directory()
                 ->GetOrCreateDirectory("svc"));
 
-    create_params.set_features(fuchsia::web::ContextFeatureFlags::AUDIO);
-
     return create_params;
   }
 
@@ -526,6 +525,32 @@ TEST_F(WebEngineIntegrationTest, PlayAudio) {
   EXPECT_FALSE(fake_audio_consumer_service_->instance(0)->is_muted());
 }
 
+// Check that audio cannot play when the AUDIO ContextFeatureFlag is not
+// provided.
+TEST_F(WebEngineIntegrationTest, PlayAudio_NoFlag) {
+  StartWebEngine();
+
+  // Both FilteredServiceDirectory and test data are needed.
+  fuchsia::web::CreateContextParams create_params =
+      ContextParamsWithFilteredServiceDirectory();
+  create_params.mutable_content_directories()->push_back(
+      CreateTestDataDirectoryProvider());
+  CreateContextAndFrame(std::move(create_params));
+
+  bool is_requested = false;
+  filtered_service_directory_->outgoing_directory()->AddPublicService(
+      std::make_unique<vfs::Service>(
+          [&is_requested](zx::channel channel, async_dispatcher_t* dispatcher) {
+            is_requested = true;
+          }),
+      fuchsia::media::SessionAudioConsumerFactory::Name_);
+
+  LoadUrlWithUserActivation("fuchsia-dir://testdata/play_audio.html");
+
+  navigation_listener_->RunUntilTitleEquals("error");
+  EXPECT_FALSE(is_requested);
+}
+
 TEST_F(WebEngineIntegrationTest, PlayVideo) {
   StartWebEngine();
   CreateContextAndFrame(ContextParamsWithAudioAndTestData());

media/audio/fuchsia/audio_manager_fuchsia.cc

@@ -6,7 +6,9 @@
 
 #include <memory>
 
+#include "base/command_line.h"
 #include "media/audio/fuchsia/audio_output_stream_fuchsia.h"
+#include "media/base/media_switches.h"
 
 namespace media {
 
@@ -31,6 +33,11 @@ bool AudioManagerFuchsia::HasAudioInputDevices() {
 
 void AudioManagerFuchsia::GetAudioInputDeviceNames(
     AudioDeviceNames* device_names) {
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kDisableAudioInput)) {
+    return;
+  }
+
   // TODO(crbug.com/852834): Fuchsia currently doesn't provide an API for device
   // enumeration. Update this method when that functionality is implemented.
   *device_names = {AudioDeviceName::CreateDefault()};
@@ -38,6 +45,11 @@ void AudioManagerFuchsia::GetAudioInputDeviceNames(
 
 void AudioManagerFuchsia::GetAudioOutputDeviceNames(
     AudioDeviceNames* device_names) {
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kDisableAudioOutput)) {
+    return;
+  }
+
   // TODO(crbug.com/852834): Fuchsia currently doesn't provide an API for device
   // enumeration. Update this method when that functionality is implemented.
   *device_names = {AudioDeviceName::CreateDefault()};

media/base/media_switches.cc

@@ -78,6 +78,7 @@ const char kEnableProtectedVideoBuffers[] = "enable-protected-video-buffers";
 const char kForceProtectedVideoOutputBuffers[] =
     "force-protected-video-output-buffers";
 
+const char kDisableAudioInput[] = "disable-audio-input";
 #endif  // defined(OS_FUCHSIA)
 
 #if defined(USE_CRAS)

media/base/media_switches.h

@@ -51,6 +51,7 @@ MEDIA_EXPORT extern const char kWaveOutBuffers[];
 #if defined(OS_FUCHSIA)
 MEDIA_EXPORT extern const char kEnableProtectedVideoBuffers[];
 MEDIA_EXPORT extern const char kForceProtectedVideoOutputBuffers[];
+MEDIA_EXPORT extern const char kDisableAudioInput[];
 #endif
 
 #if defined(OS_CHROMEOS)