Enable tests disabled for MemoryDumpManager DCHECK

sky's crrev.com/c/1233174 resolved the destruction threading
issue.

Bug: 874089, 884589
Change-Id: I35b2ffee918626b6d83e497ff0a0d3dae7f27024
Reviewed-on: https://chromium-review.googlesource.com/1241315Reviewed-by: James Cook <jamescook@chromium.org>
Commit-Queue: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#593700}

testing/buildbot/filters/chromeos.single_process_mash.content_browsertests.filter

@@ -90,50 +90,6 @@
 -WebContentsVideoCaptureDeviceBrowserTestP.*
 
 
-# Flakily fails MemoryDumpManager::UnregisterDumpProviderInternal DCHECK.
-# https://crbug.com/884589
--File/MediaTest.VideoBear12DepthVP9/0
--File/MediaTest.VideoBearHighBitDepthVP9/0
--File/MediaTest.VideoBearMp4Vp9/0
--File/MediaTest.VideoBearSilentTheora/0
--File/MediaTest.VideoBearTheora/0
--File/MediaTest.VideoBearWebm/0
--File/MediaTest.VideoTulipWebm/0
--Http/MediaTest.VideoBearHighBitDepthVP9/0
--Http/MediaTest.VideoBearMp4Vp9/0
--Http/MediaTest.VideoBearTheora/0
--Http/MediaTest.VideoTulipWebm/0
--MediaRedirectTest.CanPlayHiddenWebm
--MediaSourceTest.ConfigChangeVideo
--MediaSourceTest.Playback_VideoAudio_WebM
--MediaSourceTest.Playback_VideoOnly_WebM
--MediaTest.Navigate
--MSE_ClearKey/EncryptedMediaTest.ConfigChangeVideo_ClearToClear/0
--MSE_ClearKey/EncryptedMediaTest.ConfigChangeVideo_ClearToEncrypted/0
--MSE_ClearKey/EncryptedMediaTest.ConfigChangeVideo_EncryptedToClear/0
--MSE_ClearKey/EncryptedMediaTest.ConfigChangeVideo_EncryptedToEncrypted/0
--MSE_ClearKey/EncryptedMediaTest.FrameSizeChangeVideo/0
--MSE_ClearKey/EncryptedMediaTest.Playback_AudioClearVideo_WebM/0
--MSE_ClearKey/EncryptedMediaTest.Playback_VideoAudio_WebM/0
--MSE_ClearKey/EncryptedMediaTest.Playback_VideoAudio_WebM_Opus/0
--MSE_ClearKey/EncryptedMediaTest.Playback_VideoClearAudio_WebM/0
--MSE_ClearKey/EncryptedMediaTest.Playback_VideoClearAudio_WebM_Opus/0
--MSE_ClearKey/EncryptedMediaTest.Playback_VideoOnly_MP4_VP9/0
--MSE_ClearKey/EncryptedMediaTest.Playback_VideoOnly_WebM/0
--MSE_ClearKey/EncryptedMediaTest.Playback_VideoOnly_WebM_Fullsample/0
--MSE_ClearKey/EncryptedMediaTest.Playback_VideoOnly_WebM_Subsample/0
--MSE_ClearKey/EncryptedMediaTest.Playback_VideoOnly_WebM_Subsample/0
--SitePerProcessAutoplayBrowserTest.PropagateUserGestureFlag
--SRC_ClearKey/EncryptedMediaTest.Playback_AudioClearVideo_WebM/0
--SRC_ClearKey/EncryptedMediaTest.Playback_VideoAudio_WebM/0
--SRC_ClearKey/EncryptedMediaTest.Playback_VideoAudio_WebM_Opus/0
--SRC_ClearKey/EncryptedMediaTest.Playback_VideoClearAudio_WebM/0
--SRC_ClearKey/EncryptedMediaTest.Playback_VideoClearAudio_WebM_Opus/0
--SRC_ClearKey/EncryptedMediaTest.Playback_VideoOnly_WebM/0
--SRC_ClearKey/EncryptedMediaTest.Playback_VideoOnly_WebM_Fullsample/0
--SRC_ClearKey/EncryptedMediaTest.Playback_VideoOnly_WebM_Subsample/0
-
-
 # DCHECK(!event->IsPointerEvent()) fail. https://crbug.com/884342
 -MouseLatencyBrowserTest.CoalescedMouseWheelsCorrectlyTerminated