[Video Capture Service, ChromeOS] Enable service by default

Bug: 820608
Change-Id: I8b6831e3b8b5e6070b8e712dba5c9588e6277f8e
Reviewed-on: https://chromium-review.googlesource.com/c/1258986Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Commit-Queue: Christian Fremerey <chfremer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#596437}

content/public/common/content_features.cc

@@ -247,7 +247,7 @@ const base::Feature kMojoSessionStorage{"MojoSessionStorage",
 // Enables/disables the video capture service.
 const base::Feature kMojoVideoCapture {
   "MojoVideoCapture",
-#if defined(OS_MACOSX) || defined(OS_WIN)
+#if defined(OS_MACOSX) || defined(OS_WIN) || defined(OS_CHROMEOS)
       base::FEATURE_ENABLED_BY_DEFAULT
 #else
       base::FEATURE_DISABLED_BY_DEFAULT