ozone: Add OzoneWindowFactory & OzoneWindow

ui/gfx/ozone/surface_factory_ozone.h

Index: ui/gfx/ozone/surface_factory_ozone.h
diff --git a/ui/gfx/ozone/surface_factory_ozone.h b/ui/gfx/ozone/surface_factory_ozone.h
index 26cb7607706709e9ce3e8947d47a38cc0ff71f5f..ad871a1008d60c4aaafb4f4465e448f7cb0ad884 100644
--- a/ui/gfx/ozone/surface_factory_ozone.h
+++ b/ui/gfx/ozone/surface_factory_ozone.h
@@ -23,6 +23,12 @@ class OverlayCandidatesOzone;
 class SurfaceOzone;
 typedef intptr_t NativeBufferOzone;
 
+// Widget for use by platforms that only support one surface at a time.
+// This is probably not useful for any real platform, but it makes
+// implementing simple platforms with only one surface easier.
+GFX_EXPORT extern const gfx::AcceleratedWidget
+  kDefaultAcceleratedWidgetForSingleWindow;
+
 // The Ozone interface allows external implementations to hook into Chromium to
 // provide a system specific implementation. The Ozone interface supports two
 // drawing modes: 1) accelerated drawing through EGL and 2) software drawing
@@ -105,11 +111,6 @@ class GFX_EXPORT SurfaceFactoryOzone {
   // display connection for the native display.
   virtual intptr_t GetNativeDisplay();
 
-  // Obtains an AcceleratedWidget backed by a native Linux framebuffer.
-  // The  returned AcceleratedWidget is an opaque token that must realized
-  // before it can be used to create a GL surface.
-  virtual gfx::AcceleratedWidget GetAcceleratedWidget() = 0;
-
   // Create a surface for the specified gfx::AcceleratedWidget.
   virtual scoped_ptr<SurfaceOzone> CreateSurfaceForWidget(
       gfx::AcceleratedWidget widget);