media: Support creation and SetCdm() for mojo based CDM.

media/mojo/services/BUILD.gn

Index: media/mojo/services/BUILD.gn
diff --git a/media/mojo/services/BUILD.gn b/media/mojo/services/BUILD.gn
index c014a00f45f94bf44bd8ac26618f862f4674c8a4..acbf3cbeeac01c39029e24cf17e14f3ace257f29 100644
--- a/media/mojo/services/BUILD.gn
+++ b/media/mojo/services/BUILD.gn
@@ -46,6 +46,8 @@ source_set("cdm_proxy") {
   sources = [
     "mojo_cdm.cc",
     "mojo_cdm.h",
+    "mojo_cdm_factory.cc",
+    "mojo_cdm_factory.h",
     "mojo_type_trait.h",
   ]
 }
@@ -67,6 +69,10 @@ source_set("cdm_service") {
     "mojo_cdm_promise.h",
     "mojo_cdm_service.cc",
     "mojo_cdm_service.h",
+    "mojo_cdm_service_context.cc",
+    "mojo_cdm_service_context.h",
+    "mojo_cdm_factory_service.cc",
+    "mojo_cdm_factory_service.h",
     "mojo_type_trait.h",
   ]
 }
@@ -157,6 +163,7 @@ if (!is_component_build) {
     ]
 
     deps = [
+      ":cdm_service",
       ":renderer_service",
       "//mojo/application",
       "//mojo/public/c/system:for_shared_library",