Revert of Disable WebRtcVideoQualityBrowserTest.TestVideoQualityH264/0 on Win...

Revert of Disable WebRtcVideoQualityBrowserTest.TestVideoQualityH264/0 on Win bots. (patchset #2 id:20001 of https://codereview.chromium.org/2893523004/ )

Reason for revert:
This test passes after the fixes on issue webrtc:7532. See the explanation https://bugs.chromium.org/p/chromium/issues/detail?id=722746#c21 for how they are related.

Original issue's description:
> Disable WebRtcVideoQualityBrowserTest.TestVideoQualityH264/0 on Win bots.
>
> BUG=chromium:722746
>
> Review-Url: https://codereview.chromium.org/2893523004
> Cr-Commit-Position: refs/heads/master@{#472824}
> Committed: https://chromium.googlesource.com/chromium/src/+/7498e9b31a8ed8fd1d1fac071916cf824e48e2c5

TBR=tommi@chromium.org,philipel@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=chromium:722746

Review-Url: https://codereview.chromium.org/2903463002
Cr-Commit-Position: refs/heads/master@{#473760}

chrome/browser/media/webrtc/webrtc_video_quality_browsertest.cc

@@ -357,15 +357,8 @@ IN_PROC_BROWSER_TEST_P(WebRtcVideoQualityBrowserTest,
 
 #if BUILDFLAG(RTC_USE_H264)
 
-// TODO(philipel): Remove disable condition when H264 flakyness has been
-//                 investigated (crbug.com/722746).
-#if defined(OS_WIN)
-#define MAYBE_TestVideoQualityH264 DISABLED_TestVideoQualityH264
-#else
-#define MAYBE_TestVideoQualityH264 MANUAL_TestVideoQualityH264
-#endif
 IN_PROC_BROWSER_TEST_P(WebRtcVideoQualityBrowserTest,
-                       MAYBE_TestVideoQualityH264) {
+                       MANUAL_TestVideoQualityH264) {
   base::ThreadRestrictions::ScopedAllowIO allow_io;
   // Only run test if run-time feature corresponding to |rtc_use_h264| is on.
   if (!base::FeatureList::IsEnabled(content::kWebRtcH264WithOpenH264FFmpeg)) {