Implement a runtime headless mode for Linux

content/browser/compositor/gpu_process_transport_factory.cc

 // Copyright 2014 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.
 
 #include "content/browser/compositor/gpu_process_transport_factory.h"
 
 #include <string>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 178 matching lines @@
 
   // Make sure the lost context callback doesn't try to run during destruction.
   callback_factory_.InvalidateWeakPtrs();
 
   task_graph_runner_->Shutdown();
 }
 
 std::unique_ptr<cc::SoftwareOutputDevice>
 GpuProcessTransportFactory::CreateSoftwareOutputDevice(
     ui::Compositor* compositor) {
+  base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
+  if (command_line->HasSwitch(switches::kHeadless))
+    return base::WrapUnique(new cc::SoftwareOutputDevice);
+
 #if defined(USE_AURA)
   if (service_manager::ServiceManagerIsRemote()) {
     NOTREACHED();
     return nullptr;
   }
 #endif
 
 #if defined(OS_WIN)
   return std::unique_ptr<cc::SoftwareOutputDevice>(
       new SoftwareOutputDeviceWin(software_backing_.get(), compositor));
@@ skipping 672 matching lines @@
       shared_vulkan_context_provider_ =
           cc::VulkanInProcessContextProvider::Create();
     }
 
     shared_vulkan_context_provider_initialized_ = true;
   }
   return shared_vulkan_context_provider_;
 }
 
 }  // namespace content