Cast tunnel_socket to ProxyClientSocket instead of HttpProxyClientSocket.
Cast tunnel_socket to ProxyClientSocket instead of HttpProxyClientSocket.

BUG=453126
R=rch@chromium.org

Review URL: https://codereview.chromium.org/885233002

Cr-Commit-Position: refs/heads/master@{#313954}
(cherry picked from commit 684f44bd654c65ed515fdb1c38536530ea66254f)

Review URL: https://codereview.chromium.org/949483003

Cr-Commit-Position: 665a5787e4610f1ec55d3a4e2f02ab0724e38987@{#348}
Cr-Branched-From: 4cd5f18d847990599feba509541d8a7b9a16883a@{#310958}

jaruba/chromium.src,markYoungH/chromium.src,mohamed--abdel-maksoud/chromium.src,krieger-od/nwjs_chromium.src,M4sse/chromium.src,markYoungH/chromium.src,M4sse/chromium.src,mohamed--abdel-maksoud/chromium.src,dushu1203/chromium.src,M4sse/chromium.src,dushu1203/chromium.src,Jonekee/chromium.src,Jonekee/chromium.src,dednal/chromium.src,dushu1203/chromium.src,dednal/chromium.src,mohamed--abdel-maksoud/chromium.src,krieger-od/nwjs_chromium.src,Jonekee/chromium.src,dushu1203/chromium.src,dushu1203/chromium.src,mohamed--abdel-maksoud/chromium.src,Jonekee/chromium.src,dednal/chromium.src,dushu1203/chromium.src,mohamed--abdel-maksoud/chromium.src,M4sse/chromium.src,M4sse/chromium.src,M4sse/chromium.src,krieger-od/nwjs_chromium.src,jaruba/chromium.src,markYoungH/chromium.src,krieger-od/nwjs_chromium.src,Jonekee/chromium.src,dednal/chromium.src,jaruba/chromium.src,markYoungH/chromium.src,krieger-od/nwjs_chromium.src,M4sse/chromium.src,M4sse/chromium.src,mohamed--abdel-maksoud/chromium.src,mohamed--abdel-maksoud/chromium.src,jaruba/chromium.src,M4sse/chromium.src,mohamed--abdel-maksoud/chromium.src,Jonekee/chromium.src,mohamed--abdel-maksoud/chromium.src,dednal/chromium.src,krieger-od/nwjs_chromium.src,markYoungH/chromium.src,krieger-od/nwjs_chromium.src,Jonekee/chromium.src,markYoungH/chromium.src,krieger-od/nwjs_chromium.src,dushu1203/chromium.src,jaruba/chromium.src,krieger-od/nwjs_chromium.src,markYoungH/chromium.src,markYoungH/chromium.src,jaruba/chromium.src,markYoungH/chromium.src,jaruba/chromium.src,mohamed--abdel-maksoud/chromium.src,jaruba/chromium.src,Jonekee/chromium.src,dushu1203/chromium.src,Jonekee/chromium.src,M4sse/chromium.src,dushu1203/chromium.src,dednal/chromium.src,dednal/chromium.src,jaruba/chromium.src,mohamed--abdel-maksoud/chromium.src,krieger-od/nwjs_chromium.src,dednal/chromium.src,Jonekee/chromium.src,M4sse/chromium.src,krieger-od/nwjs_chromium.src,jaruba/chromium.src,markYoungH/chromium.src,dednal/chromium.src,dednal/chromium.src,Jonekee/chromium.src,dushu1203/chromium.src,dednal/chromium.src,jaruba/chromium.src,dushu1203/chromium.src,markYoungH/chromium.src