ozone: Introduce ClientPixmap and ClientPixmapFactory for non-GPU processes.

ui/ozone/public/ozone_platform.h

Index: ui/ozone/public/ozone_platform.h
diff --git a/ui/ozone/public/ozone_platform.h b/ui/ozone/public/ozone_platform.h
index 590104b8428a8145afcb8c0f8da5a4a2e95ed591..0e8fb33b29751546eed58bae1e73014d83421ce4 100644
--- a/ui/ozone/public/ozone_platform.h
+++ b/ui/ozone/public/ozone_platform.h
@@ -8,6 +8,10 @@
 #include "base/memory/scoped_ptr.h"
 #include "ui/ozone/ozone_export.h"
 
+namespace base {
+struct FileDescriptor;
+}
+
 namespace gfx {
 class Rect;
 }
@@ -68,6 +72,8 @@ class OZONE_EXPORT OzonePlatform {
       const gfx::Rect& bounds) = 0;
   virtual scoped_ptr<ui::NativeDisplayDelegate>
       CreateNativeDisplayDelegate() = 0;
+  // Return virtual device FD which Renderer uses to manage a native surface.
+  virtual base::FileDescriptor GetVirtualDeviceFd() = 0;
 
  private:
   virtual void InitializeUI() = 0;