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

ui/ozone/platform/caca/ozone_platform_caca.cc

Index: ui/ozone/platform/caca/ozone_platform_caca.cc
diff --git a/ui/ozone/platform/caca/ozone_platform_caca.cc b/ui/ozone/platform/caca/ozone_platform_caca.cc
index fdfebe22402d4d149a200af974b1767513610402..811c210d6112796417b786a692576adf2928dfe1 100644
--- a/ui/ozone/platform/caca/ozone_platform_caca.cc
+++ b/ui/ozone/platform/caca/ozone_platform_caca.cc
@@ -15,6 +15,7 @@
 #include "ui/ozone/public/gpu_platform_support.h"
 #include "ui/ozone/public/gpu_platform_support_host.h"
 #include "ui/ozone/public/input_controller.h"
+#include "ui/ozone/public/native_pixmap_client.h"
 #include "ui/ozone/public/ozone_platform.h"
 #include "ui/ozone/public/system_input_injector.h"
 
@@ -89,10 +90,23 @@ class OzonePlatformCaca : public OzonePlatform {
   DISALLOW_COPY_AND_ASSIGN(OzonePlatformCaca);
 };
 
+class NativePixmapClientCaca : public NativePixmapClient {
+ public:
+  NativePixmapClientCaca() {}
+  ~NativePixmapClientCaca() override {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(NativePixmapClientCaca);
+};
+
 }  // namespace
 
 OzonePlatform* CreateOzonePlatformCaca() {
   return new OzonePlatformCaca;
 }
 
+NativePixmapClient* CreateNativePixmapClientCaca() {
+  return new NativePixmapClientCaca;
+}
+
 }  // namespace ui