Enable overriding interface binders for any services running in current process.

services/service_manager/public/cpp/service_context.h

Index: services/service_manager/public/cpp/service_context.h
diff --git a/services/service_manager/public/cpp/service_context.h b/services/service_manager/public/cpp/service_context.h
index 451f1ad0c8e297a65de8f14350be03ef6f6498b0..2a2886dd52c98a014f6045feb90d3cc28cf2adbe 100644
--- a/services/service_manager/public/cpp/service_context.h
+++ b/services/service_manager/public/cpp/service_context.h
@@ -13,6 +13,7 @@
 #include "base/memory/weak_ptr.h"
 #include "mojo/public/cpp/bindings/binding.h"
 #include "mojo/public/cpp/system/core.h"
+#include "services/service_manager/public/cpp/binder_registry.h"
 #include "services/service_manager/public/cpp/connector.h"
 #include "services/service_manager/public/cpp/service.h"
 #include "services/service_manager/public/interfaces/connector.mojom.h"
@@ -104,6 +105,20 @@ class ServiceContext : public mojom::Service {
   // disconnection from the Service Manager.
   void QuitNow();
 
+  // Overrides the interface binder for |interface_name| of |service_name|.
+  // This is a process-wide override, means that |binder| can intercept requests

[Ken Rockot(use gerrit already), 2017/05/11 02:32:08]

nit: means=meaning

[leonhsl(Using Gerrit), 2017/05/11 03:10:04]

Done.

+  // against only those |service_name| service instances running in the same
+  // process with caller of this function.
+  static void SetGlobalBinderForTesting(
+      const std::string& service_name,
+      const std::string& interface_name,
+      const BinderRegistry::Binder& binder,
+      const scoped_refptr<base::SingleThreadTaskRunner>& task_runner = nullptr);
+
+  // Clears all overridden interface binders for service |service_name| set via
+  // SetGlobalBinderForTesting() before.

[Ken Rockot(use gerrit already), 2017/05/11 02:32:08]

nit: can remove "before"

[leonhsl(Using Gerrit), 2017/05/11 03:10:04]

Done.

+  static void ClearGlobalBindersForTesting(const std::string& service_name);
+
  private:
   friend class service_manager::Service;