Reland "Enable video capture service by default on platforms where it…

… is rolling out with M61."

This is a reland of 1e2e99e

The reason for the revert was a Webkit layout test failing with this CL. With
https://chromium-review.googlesource.com/c/chromium/src/+/806442 landed to fix that test,
this CL should now be able to reland without modification.

Original change's description:
> Enable video capture service by default on platforms where it is rolling
> out with M61.
>
> Bug: 721812
> Change-Id: I1de0f625a1fb106e2dea664675e94267e66fc2fd
> Reviewed-on: https://chromium-review.googlesource.com/719416
> Commit-Queue: Christian Fremerey <chfremer@chromium.org>
> Reviewed-by: Emircan Uysaler <emircan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#517761}

TBR=emircan@chromium.org

Bug: 721812
Change-Id: If69cdb660b0b97a28084b6bd0610234d5abb232f
Reviewed-on: https://chromium-review.googlesource.com/809530
Reviewed-by: Christian Fremerey <chfremer@chromium.org>
Commit-Queue: Christian Fremerey <chfremer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#521800}

content/browser/renderer_host/media/media_stream_manager_unittest.cc

@@ -18,6 +18,7 @@
 #include "content/browser/browser_thread_impl.h"
 #include "content/browser/renderer_host/media/media_stream_manager.h"
 #include "content/browser/renderer_host/media/media_stream_ui_proxy.h"
+#include "content/browser/renderer_host/media/mock_video_capture_provider.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/test/test_browser_thread_bundle.h"
 #include "media/audio/audio_device_description.h"
@@ -43,6 +44,7 @@
 #endif
 
 using testing::_;
+using testing::Invoke;
 
 namespace content {
 
@@ -138,9 +140,19 @@ class MediaStreamManagerTest : public ::testing::Test {
     audio_manager_ = std::make_unique<MockAudioManager>();
     audio_system_ =
         std::make_unique<media::AudioSystemImpl>(audio_manager_.get());
+    auto video_capture_provider = std::make_unique<MockVideoCaptureProvider>();
+    video_capture_provider_ = video_capture_provider.get();
     media_stream_manager_ = std::make_unique<MediaStreamManager>(
-        audio_system_.get(), audio_manager_->GetTaskRunner());
+        audio_system_.get(), audio_manager_->GetTaskRunner(),
+        std::move(video_capture_provider));
     base::RunLoop().RunUntilIdle();
+
+    ON_CALL(*video_capture_provider_, DoGetDeviceInfosAsync(_))
+        .WillByDefault(Invoke(
+            [](VideoCaptureProvider::GetDeviceInfosCallback& result_callback) {
+              std::vector<media::VideoCaptureDeviceInfo> stub_results;
+              base::ResetAndReturn(&result_callback).Run(stub_results);
+            }));
   }
 
   ~MediaStreamManagerTest() override { audio_manager_->Shutdown(); }
@@ -176,6 +188,7 @@ class MediaStreamManagerTest : public ::testing::Test {
   content::TestBrowserThreadBundle thread_bundle_;
   std::unique_ptr<MockAudioManager> audio_manager_;
   std::unique_ptr<media::AudioSystem> audio_system_;
+  MockVideoCaptureProvider* video_capture_provider_;
   base::RunLoop run_loop_;
 
  private:

content/browser/renderer_host/media/service_video_capture_provider.cc

@@ -20,20 +20,28 @@ class ServiceConnectorImpl
  public:
   ServiceConnectorImpl() {
     DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
-    connector_ = content::ServiceManagerConnection::GetForProcess()
-                     ->GetConnector()
-                     ->Clone();
-    DETACH_FROM_SEQUENCE(sequence_checker_);
+    // In unit test environments, there may not be any connector.
+    auto* connection = content::ServiceManagerConnection::GetForProcess();
+    if (!connection)
+      return;
+    auto* connector = connection->GetConnector();
+    if (!connector)
+      return;
+    connector_ = connector->Clone();
   }
 
   void BindFactoryProvider(
       video_capture::mojom::DeviceFactoryProviderPtr* provider) override {
+    if (!connector_) {
+      CHECK(false) << "Attempted to connect to the video capture service from "
+                      "a process that does not provide a "
+                      "ServiceManagerConnection";
+    }
     connector_->BindInterface(video_capture::mojom::kServiceName, provider);
   }
 
  private:
   std::unique_ptr<service_manager::Connector> connector_;
-  SEQUENCE_CHECKER(sequence_checker_);
 };
 
 }  // anonymous namespace

services/video_capture/public/cpp/constants.cc

@@ -4,9 +4,18 @@
 
 #include "services/video_capture/public/cpp/constants.h"
 
+#include "build/build_config.h"
+
 namespace video_capture {
 
-const base::Feature kMojoVideoCapture{"MojoVideoCapture",
-                                      base::FEATURE_DISABLED_BY_DEFAULT};
+const base::Feature kMojoVideoCapture {
+  "MojoVideoCapture",
+#if (defined(OS_LINUX) && !defined(OS_CHROMEOS)) || defined(OS_MACOSX) || \
+    defined(OS_WIN)
+      base::FEATURE_ENABLED_BY_DEFAULT
+#else
+      base::FEATURE_DISABLED_BY_DEFAULT
+#endif
+};
 
 }  // namespace video_capture