Add a new ozone switch to enable surfaceless output mode.

ui/ozone/platform/dri/gbm_surface_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 "ui/ozone/platform/dri/gbm_surface_factory.h"
 
 #include <EGL/egl.h>
 #include <gbm.h>
 
 #include "base/files/file_path.h"
@@ skipping 79 matching lines @@
   add_gl_library.Run(gles_library);
 
   return true;
 }
 
 scoped_ptr<SurfaceOzoneEGL> GbmSurfaceFactory::CreateEGLSurfaceForWidget(
     gfx::AcceleratedWidget widget) {
   DCHECK(state_ == INITIALIZED);
   ResetCursor(widget);
 
-  if (allow_surfaceless_) {
-    return scoped_ptr<SurfaceOzoneEGL>(
-        new GbmSurfaceless(screen_manager_->GetDisplayController(widget)));
-  } else {
-    scoped_ptr<GbmSurface> surface(
-        new GbmSurface(screen_manager_->GetDisplayController(widget),
-                       device_,
-                       drm_));
-    if (!surface->Initialize())
-      return scoped_ptr<SurfaceOzoneEGL>();
+  scoped_ptr<GbmSurface> surface(
+      new GbmSurface(screen_manager_->GetDisplayController(widget),
+                     device_,
+                     drm_));
+  if (!surface->Initialize())
+    return scoped_ptr<SurfaceOzoneEGL>();
 
-    return surface.PassAs<SurfaceOzoneEGL>();
-  }
+  return surface.PassAs<SurfaceOzoneEGL>();
+}
+
+scoped_ptr<SurfaceOzoneEGL> GbmSurfaceFactory::CreateEmptyEGLSurfaceForWidget(
+    gfx::AcceleratedWidget widget) {
+  if (!allow_surfaceless_)
+    return scoped_ptr<SurfaceOzoneEGL>();
+  return scoped_ptr<SurfaceOzoneEGL>(
+      new GbmSurfaceless(screen_manager_->GetDisplayController(widget)));
 }
 
 scoped_refptr<ui::NativePixmap> GbmSurfaceFactory::CreateNativePixmap(
     gfx::Size size,
     BufferFormat format) {
   scoped_refptr<GbmBuffer> buffer = GbmBuffer::CreateBuffer(
       drm_, device_, format, size, true);
   if (!buffer)
     return NULL;
 
   return scoped_refptr<GbmPixmap>(new GbmPixmap(buffer));
 }
 
 bool GbmSurfaceFactory::CanShowPrimaryPlaneAsOverlay() {
   return allow_surfaceless_;
 }
 
 }  // namespace ui