Revert of headless: Allow protocol handler customization

headless/public/headless_browser.cc

Index: headless/public/headless_browser.cc
diff --git a/headless/public/headless_browser.cc b/headless/public/headless_browser.cc
index 0b4e17f1e7e14143fadfae104a915ae9225ef286..07d263641ac90fdd82feffc9131a158c89593088 100644
--- a/headless/public/headless_browser.cc
+++ b/headless/public/headless_browser.cc
@@ -65,11 +65,6 @@
   return *this;
 }
 
-Builder& Builder::SetProtocolHandlers(ProtocolHandlerMap protocol_handlers) {
-  options_.protocol_handlers = std::move(protocol_handlers);
-  return *this;
-}
-
 Options Builder::Build() {
   return std::move(options_);
 }