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

ui/ozone/platform/test/ozone_platform_test.h

Index: ui/ozone/platform/test/ozone_platform_test.h
diff --git a/ui/ozone/platform/test/ozone_platform_test.h b/ui/ozone/platform/test/ozone_platform_test.h
index fb25fd69f557a01cbe209c3f38e3123adbf8e581..54661219d4d429e4dc1bb4b9a9bcdc6f57c5b0c7 100644
--- a/ui/ozone/platform/test/ozone_platform_test.h
+++ b/ui/ozone/platform/test/ozone_platform_test.h
@@ -7,11 +7,15 @@
 
 namespace ui {
 
+class OzoneClient;
 class OzonePlatform;
 
 // Constructor hook for use in ozone_platform_list.cc
 OzonePlatform* CreateOzonePlatformTest();
 
+// Constructor hook for use in constructor_client_list.cc
+OzoneClient* CreateOzoneClientTest();
+
 }  // namespace ui
 
 #endif  // UI_OZONE_PLATFORM_TEST_OZONE_PLATFORM_TEST_H_