headless: Make HeadlessBrowser::Options move-only

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 6ff0a0c35ff00fa081f6429764dea3e1b469d2f0..07d263641ac90fdd82feffc9131a158c89593088 100644
--- a/headless/public/headless_browser.cc
+++ b/headless/public/headless_browser.cc
@@ -23,10 +23,12 @@ Options::Options(int argc, const char** argv)
       message_pump(nullptr),
       single_process_mode(false) {}
 
-Options::Options(const Options& other) = default;
+Options::Options(Options&& options) = default;
 
 Options::~Options() {}
 
+Options& Options::operator=(Options&& options) = default;
+
 Builder::Builder(int argc, const char** argv) : options_(argc, argv) {}
 
 Builder::Builder() : options_(0, nullptr) {}
@@ -64,7 +66,7 @@ Builder& Builder::SetSingleProcessMode(bool single_process_mode) {
 }
 
 Options Builder::Build() {
-  return options_;
+  return std::move(options_);
 }
 
 }  // namespace headless