Reland "Disable flaky capture unittests on Linux."

This reverts commit a99efe4b25.

Reason for revert: Still flaky.

Original change's description:
> Revert "Disable flaky capture unittests on Linux."
> 
> This reverts commit 46bf6346e6.
> 
> Reason for revert: New webcam plugged in; let's see if they're still flaky.
> 
> Original change's description:
> > Disable flaky capture unittests on Linux.
> > 
> > The tests went flaky when we replaced the bot and get VIDIOC_STREAMON
> > errors about 25% of the builds. I have no idea to fix that; we tried
> > replacing the webcam and moving it around in the USB ports and that
> > didn't help. See http://crbug.com/828568 for discussion.
> > 
> > Bug: chromium:831514
> > Change-Id: Ic55c09a16a22dd0402c3360b710e310c733ec5f9
> > Reviewed-on: https://chromium-review.googlesource.com/1016301
> > Reviewed-by: Christian Fremerey <chfremer@chromium.org>
> > Commit-Queue: Christian Fremerey <chfremer@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#552165}
> 
> TBR=phoglund@chromium.org,chfremer@chromium.org
> 
> # Not skipping CQ checks because original CL landed > 1 day ago.
> 
> Bug: chromium:831514, chromium:828568
> Change-Id: I01b21c5073e79e004c74430cc6eeb3422b602745
> Reviewed-on: https://chromium-review.googlesource.com/1039425
> Reviewed-by: Patrik Höglund <phoglund@chromium.org>
> Commit-Queue: Patrik Höglund <phoglund@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#555342}

TBR=phoglund@chromium.org,chfremer@chromium.org

Change-Id: I9c976f8bb2e0812029d13ae020896bebadf4ef1c
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:831514, chromium:828568
Reviewed-on: https://chromium-review.googlesource.com/1041945
Commit-Queue: Patrik Höglund <phoglund@chromium.org>
Reviewed-by: Patrik Höglund <phoglund@chromium.org>
Cr-Commit-Position: refs/heads/master@{#555996}

media/capture/video/video_capture_device_unittest.cc

@@ -61,11 +61,13 @@
 #define MAYBE_CaptureMjpeg DISABLED_CaptureMjpeg
 #define MAYBE_TakePhoto TakePhoto
 #define MAYBE_GetPhotoState GetPhotoState
+#define MAYBE_CaptureWithSize CaptureWithSize
 #elif defined(OS_WIN)
 #define MAYBE_AllocateBadSize AllocateBadSize
 #define MAYBE_CaptureMjpeg CaptureMjpeg
 #define MAYBE_TakePhoto TakePhoto
 #define MAYBE_GetPhotoState GetPhotoState
+#define MAYBE_CaptureWithSize CaptureWithSize
 #elif defined(OS_ANDROID)
 #define MAYBE_AllocateBadSize AllocateBadSize
 #define MAYBE_CaptureMjpeg CaptureMjpeg
@@ -79,19 +81,24 @@
 #define MAYBE_GetPhotoState GetPhotoState
 #define MAYBE_CaptureWithSize CaptureWithSize
 #elif defined(OS_LINUX)
+// All tests are flaky on Linux: https://crbug.com/831514. Note: the stuff in
+// the next comment is a separate issue.
+
 // AllocateBadSize will hang when a real camera is attached and if more than one
 // test is trying to use the camera (even across processes). Do NOT renable
 // this test without fixing the many bugs associated with it:
 // http://crbug.com/94134 http://crbug.com/137260 http://crbug.com/417824
 #define MAYBE_AllocateBadSize DISABLED_AllocateBadSize
-#define MAYBE_CaptureMjpeg CaptureMjpeg
-#define MAYBE_TakePhoto TakePhoto
-#define MAYBE_GetPhotoState GetPhotoState
+#define MAYBE_CaptureMjpeg DISABLED_CaptureMjpeg
+#define MAYBE_TakePhoto DISABLED_TakePhoto
+#define MAYBE_GetPhotoState DISABLED_GetPhotoState
+#define MAYBE_CaptureWithSize DISABLED_CaptureWithSize
 #else
 #define MAYBE_AllocateBadSize AllocateBadSize
 #define MAYBE_CaptureMjpeg CaptureMjpeg
 #define MAYBE_TakePhoto DISABLED_TakePhoto
 #define MAYBE_GetPhotoState DISABLED_GetPhotoState
+#define MAYBE_CaptureWithSize CaptureWithSize
 #endif
 
 // Wrap the TEST_P macro into another one to allow to preprocess |test_name|
@@ -489,7 +496,7 @@ TEST(VideoCaptureDeviceDescriptor, RemoveTrailingWhitespaceFromDisplayName) {
 }
 
 // Allocates the first enumerated device, and expects a frame.
-WRAPPED_TEST_P(VideoCaptureDeviceTest, CaptureWithSize) {
+WRAPPED_TEST_P(VideoCaptureDeviceTest, MAYBE_CaptureWithSize) {
   const auto descriptor = FindUsableDeviceDescriptor();
   if (!descriptor)
     return;