Revert of Eliminate ChildThread InterfaceRegistry.

content/public/test/mock_render_thread.cc

Index: content/public/test/mock_render_thread.cc
diff --git a/content/public/test/mock_render_thread.cc b/content/public/test/mock_render_thread.cc
index aeb37bb6058b230f5213b89b33d6deece4466e4e..0c02a0d3ce88aa72e948e7fc9e93a1f550239f19 100644
--- a/content/public/test/mock_render_thread.cc
+++ b/content/public/test/mock_render_thread.cc
@@ -19,6 +19,9 @@
 #include "ipc/ipc_sync_message.h"
 #include "ipc/message_filter.h"
 #include "services/service_manager/public/cpp/connector.h"
+#include "services/service_manager/public/cpp/interface_provider.h"
+#include "services/service_manager/public/cpp/interface_registry.h"
+#include "services/service_manager/public/interfaces/interface_provider_spec.mojom.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/WebKit/public/web/WebScriptController.h"
 
@@ -250,6 +253,14 @@
   return nullptr;
 }
 
+service_manager::InterfaceRegistry* MockRenderThread::GetInterfaceRegistry() {
+  if (!interface_registry_) {
+    interface_registry_ = base::MakeUnique<service_manager::InterfaceRegistry>(
+        service_manager::mojom::kServiceManager_ConnectorSpec);
+  }
+  return interface_registry_.get();
+}
+
 service_manager::Connector* MockRenderThread::GetConnector() {
   if (!connector_) {
     connector_ =