[Image Capture] Enable image capture tests with real webcams using video capture service.

This is a new attempt to enable tests that were disabled due to
flakiness on WebRTC bots (this is a roll-forward of http://crrev.com/c/896062).
This is a further attempt to get these tests to run on the bots.

NB: running the tests locally, I was able to verify that due to issues
in the UVC kernel module on Linux, the test
WebRtcImageCaptureSucceedsBrowserTest.ManipulateFocusDistance was
consistently failing with and without the video capture service. Since
the issue is not in Chromium, I am disabling the test and tracking the
work to re-enable it in a separate bug (http://crbug.com/c/957020).

I was able to run the tests locally and they passed with 3 different
cameras, namely Logitech C920, Logitech C930e, and Sonix Technoligy
Facevision.

TBR=chfremer@chromium.org
TEST=content_browsertests --gtest_filter=UsingRealWebcam* --run-manual --test-launcher-jobs=1
BUG=721812

Change-Id: I914dde51664a26ee2134d5c7a4c663bc801db9fd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1583709Reviewed-by: Guido Urdaneta <guidou@chromium.org>
Commit-Queue: Armando Miraglia <armax@chromium.org>
Cr-Commit-Position: refs/heads/master@{#654819}

content/browser/webrtc/webrtc_image_capture_browsertest.cc

@@ -23,16 +23,20 @@
 
 namespace content {
 
+// Disable FocusDistance test which fails with Logitec cameras.
+// TODO(crbug.com/957020): renable these tests when we have a way to detect
+// which device is connected and hence avoid running it if the camera is
+// Logitech.
+#define MAYBE_ManipulateFocusDistance DISABLED_ManipulateFocusDistance
+
 #if defined(OS_ANDROID)
 // TODO(crbug.com/793859): Re-enable test on Android as soon as the cause for
 // the bug is understood and fixed.
 #define MAYBE_ManipulateZoom DISABLED_ManipulateZoom
 #define MAYBE_ManipulateExposureTime DISABLED_ManipulateExposureTime
-#define MAYBE_ManipulateFocusDistance DISABLED_ManipulateFocusDistance
 #else
 #define MAYBE_ManipulateZoom ManipulateZoom
 #define MAYBE_ManipulateExposureTime ManipulateExposureTime
-#define MAYBE_ManipulateFocusDistance ManipulateFocusDistance
 #endif
 
 namespace {
@@ -159,18 +163,6 @@ class WebRtcImageCaptureSucceedsBrowserTest
     }
   }
 
-  bool RunImageCaptureTestCase(const std::string& command) override {
-    // TODO(chfremer): Enable test cases using the video capture service with
-    // real cameras as soon as root cause for https://crbug.com/733582 is
-    // understood and resolved.
-    if ((std::get<0>(GetParam()) == TargetCamera::REAL_WEBCAM) &&
-        (std::get<1>(GetParam()).use_video_capture_service)) {
-      LOG(INFO) << "Skipping this test case";
-      return true;
-    }
-    return WebRtcImageCaptureBrowserTestBase::RunImageCaptureTestCase(command);
-  }
-
  private:
   base::test::ScopedFeatureList scoped_feature_list_;