headless: Enable GL support by default

headless/public/headless_browser.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef HEADLESS_PUBLIC_HEADLESS_BROWSER_H_
 #define HEADLESS_PUBLIC_HEADLESS_BROWSER_H_
 
 #include <memory>
 #include <string>
 #include <unordered_map>
@@ skipping 99 matching lines @@
 
   // Run the browser in single process mode instead of using separate renderer
   // processes as per default. Note that this also disables any sandboxing of
   // web content, which can be a security risk.
   bool single_process_mode;
 
   // Custom network protocol handlers. These can be used to override URL
   // fetching for different network schemes.
   ProtocolHandlerMap protocol_handlers;
 
+  // Choose the GL implementation to use for rendering. A suitable
+  // implementantion is selected by default. Setting this to an empty
+  // string can be used to disable GL rendering (e.g., WebGL support).
+  std::string gl_implementation;
+
  private:
   Options(int argc, const char** argv);
 
   DISALLOW_COPY_AND_ASSIGN(Options);
 };
 
 class HeadlessBrowser::Options::Builder {
  public:
   Builder(int argc, const char** argv);
   Builder();
   ~Builder();
 
   Builder& SetUserAgent(const std::string& user_agent);
   Builder& EnableDevToolsServer(const net::IPEndPoint& endpoint);
   Builder& SetMessagePump(base::MessagePump* message_pump);
   Builder& SetProxyServer(const net::HostPortPair& proxy_server);
   Builder& SetHostResolverRules(const std::string& host_resolver_rules);
   Builder& SetSingleProcessMode(bool single_process_mode);
   Builder& SetProtocolHandlers(ProtocolHandlerMap protocol_handlers);
+  Builder& SetGLImplementation(const std::string& gl_implementation);
 
   Options Build();
 
  private:
   Options options_;
 
   DISALLOW_COPY_AND_ASSIGN(Builder);
 };
 
 // The headless browser may need to create child processes (e.g., a renderer
@@ skipping 23 matching lines @@
 // the main loop, it will only return after HeadlessBrowser::Shutdown() is
 // called, returning the exit code for the process. It is not possible to
 // initialize the browser again after it has been torn down.
 int HeadlessBrowserMain(
     HeadlessBrowser::Options options,
     const base::Callback<void(HeadlessBrowser*)>& on_browser_start_callback);
 
 }  // namespace headless
 
 #endif  // HEADLESS_PUBLIC_HEADLESS_BROWSER_H_