Fall back to software mode if Aura can't create a GL context

content/browser/aura/gpu_process_transport_factory.cc

 // Copyright (c) 2013 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/aura/gpu_process_transport_factory.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 161 matching lines @@
 #elif defined(USE_X11)
   return scoped_ptr<cc::SoftwareOutputDevice>(new SoftwareOutputDeviceX11(
       compositor));
 #endif
 
   NOTREACHED();
   return scoped_ptr<cc::SoftwareOutputDevice>();
 }
 
 scoped_ptr<cc::OutputSurface> GpuProcessTransportFactory::CreateOutputSurface(
-    ui::Compositor* compositor) {
+    ui::Compositor* compositor, bool software_fallback) {
   PerCompositorData* data = per_compositor_data_[compositor];
   if (!data)
     data = CreatePerCompositorData(compositor);
 
   scoped_refptr<ContextProviderCommandBuffer> context_provider;
 
   CommandLine* command_line = CommandLine::ForCurrentProcess();
-  if (!command_line->HasSwitch(switches::kUIEnableSoftwareCompositing)) {
+  if (!command_line->HasSwitch(switches::kUIEnableSoftwareCompositing) &&
+      !software_fallback) {
     context_provider = ContextProviderCommandBuffer::Create(
         GpuProcessTransportFactory::CreateContextCommon(data->surface_id),
         "Compositor");
   }
 
   UMA_HISTOGRAM_BOOLEAN("Aura.CreatedGpuBrowserCompositor", !!context_provider);
 
   if (!context_provider.get()) {
     if (ui::Compositor::WasInitializedWithThread()) {
       LOG(FATAL) << "Failed to create UI context, but can't use software"
@@ skipping 290 matching lines @@
                     observer_list_,
                     OnLostResources());
 
   // Kill things that use the shared context before killing the shared context.
   lost_gl_helper.reset();
   lost_offscreen_compositor_contexts = NULL;
   lost_shared_main_thread_contexts  = NULL;
 }
 
 }  // namespace content