Enable the mojo-based serial API in the renderer behind a flag.

extensions/browser/service_registration_manager.h

Index: extensions/browser/service_registration_manager.h
diff --git a/extensions/browser/service_registration_manager.h b/extensions/browser/service_registration_manager.h
index cec84a0b9dc7b0cbbbe9514d95ccea19fe3e68af..e577de72d3507d1c02a94a5a3bbf23c5372769d6 100644
--- a/extensions/browser/service_registration_manager.h
+++ b/extensions/browser/service_registration_manager.h
@@ -5,6 +5,7 @@
 #ifndef EXTENSIONS_BROWSER_SERVICE_REGISTRATION_MANAGER_H_
 #define EXTENSIONS_BROWSER_SERVICE_REGISTRATION_MANAGER_H_
 
+#include <map>
 #include <string>
 #include <utility>
 #include <vector>
@@ -27,6 +28,8 @@ class ServiceFactoryBase {
 
   // Add this service factory to |service_registry|.
   virtual void Register(content::ServiceRegistry* service_registry) const = 0;
+
+  virtual std::string GetName() const = 0;
 };
 
 template <typename Interface>
@@ -42,6 +45,8 @@ class ServiceFactory : public ServiceFactoryBase {
     service_registry->AddService(factory_);
   }
 
+  virtual std::string GetName() const override { return Interface::Name_; }
+
  private:
   const base::Callback<void(mojo::InterfaceRequest<Interface>)> factory_;
   DISALLOW_COPY_AND_ASSIGN(ServiceFactory);
@@ -77,6 +82,24 @@ class ServiceRegistrationManager {
                            new internal::ServiceFactory<Interface>(factory))));
   }
 
+  // Overrides an existing service factory with |factory| for testing. This
+  // does not alter the permission checks used to determine whether a service
+  // is available.
+  template <typename Interface>
+  void OverrideServiceFactoryForTest(

[raymes, 2014/10/15 21:07:09]

It seems a bit nicer to me to avoid having this test code in the implementation.
Instead you could override the ServiceRegistrationManager for test with your own
one that is constructed manually (perhaps with a separate constructor that
doesn't add the services automatically).

[Sam McNally, 2014/10/20 07:21:07]

Done.

+      const base::Callback<void(mojo::InterfaceRequest<Interface>)>& factory) {
+    bool inserted =
+        test_factories_.insert(std::make_pair(
+                                   Interface::Name_,
+                                   linked_ptr<internal::ServiceFactoryBase>(
+                                       new internal::ServiceFactory<Interface>(
+                                           factory)))).second;
+    DCHECK(inserted);
+  }
+
+  // Clears any overrides created using OverrideServiceFactoryForTest().
+  void ClearOverridesForTest();
+
   // Adds the service factories appropriate for |render_frame_host| to its
   // ServiceRegistry.
   void AddToRenderFrame(content::RenderFrameHost* render_frame_host);
@@ -86,6 +109,9 @@ class ServiceRegistrationManager {
   std::vector<std::pair<std::string, linked_ptr<internal::ServiceFactoryBase>>>
       factories_;
 
+  std::map<std::string, linked_ptr<internal::ServiceFactoryBase>>
+      test_factories_;
+
   DISALLOW_COPY_AND_ASSIGN(ServiceRegistrationManager);
 };