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

ui/ozone/platform/caca/ozone_platform_caca.h

Index: ui/ozone/platform/caca/ozone_platform_caca.h
diff --git a/ui/ozone/platform/caca/ozone_platform_caca.h b/ui/ozone/platform/caca/ozone_platform_caca.h
index bf1f73520882334ad401617e4cda8956e4cf9f2f..9536e36d713df085ff2ac4d6b754d7516b7d9c7b 100644
--- a/ui/ozone/platform/caca/ozone_platform_caca.h
+++ b/ui/ozone/platform/caca/ozone_platform_caca.h
@@ -7,11 +7,15 @@
 
 namespace ui {
 
+class OzoneClient;
 class OzonePlatform;
 
 // Constructor hook for use in ozone_platform_list.cc
 OzonePlatform* CreateOzonePlatformCaca();
 
+// Constructor hook for use in constructor_client_list.cc
+OzoneClient* CreateOzoneClientCaca();
+
 }  // namespace ui
 
 #endif  // UI_OZONE_PLATFORM_CACA_OZONE_PLATFORM_CACA_H_