media: Add ProvisionFetcher mojo interface and implementation.

media/mojo/services/default_mojo_media_client.cc

Index: media/mojo/services/default_mojo_media_client.cc
diff --git a/media/mojo/services/default_mojo_media_client.cc b/media/mojo/services/default_mojo_media_client.cc
index 8751598dd3371cb3f16f5ad9d381d195eaecd94d..47b6a36a015eb59503f98958e212ccf629955d88 100644
--- a/media/mojo/services/default_mojo_media_client.cc
+++ b/media/mojo/services/default_mojo_media_client.cc
@@ -59,7 +59,8 @@ class DefaultMojoMediaClient : public PlatformMojoMediaClient {
     return audio_hardware_config_.get();
   }
 
-  scoped_ptr<CdmFactory> CreateCdmFactory() override {
+  scoped_ptr<CdmFactory> CreateCdmFactory(
+      mojo::ServiceProvider* /* service_provider */) override {
     return make_scoped_ptr(new DefaultCdmFactory());
   }