Remove the per-file entries in content/common/OWNERS for WebSocket files

There's no longer any WebSocket files under content/common/.

R=yhirano@chromium.org,jochen@chromium.org
BUG=none

Review-Url: https://codereview.chromium.org/2344613005
Cr-Commit-Position: refs/heads/master@{#418822}

content/common/OWNERS

@@ -36,11 +36,6 @@ per-file *.mojom=file://ipc/SECURITY_OWNERS
 per-file accessibility_node_data.*=dmazzoni@chromium.org
 per-file accessibility_node_data.*=dtseng@chromium.org
 
-# WebSocket
-per-file websocket.*=ricea@chromium.org
-per-file websocket.*=tyoshino@chromium.org
-per-file websocket.*=yhirano@chromium.org
-
 # DirectWrite
 per-file dwrite_font_platform_win*=scottmg@chromium.org
 per-file font_warmup_win.cc=scottmg@chromium.org