Revert of Remove shell::Loader

services/shell/shell.cc

Index: services/shell/shell.cc
diff --git a/services/shell/shell.cc b/services/shell/shell.cc
index a542ae4769e481d48514d785e9650414d4d09d3a..35049dd41f30873ef65a2161d14f8a1c5f548fde 100644
--- a/services/shell/shell.cc
+++ b/services/shell/shell.cc
@@ -120,8 +120,10 @@
       allow_any_application_(capability_spec.required.count("*") == 1),
       pid_receiver_binding_(this),
       weak_factory_(this) {
-    if (identity_.name() == kShellName)
+    if (identity_.name() == kShellName ||
+        shell_->GetLoaderForName(identity_.name())) {
       pid_ = base::Process::Current().Pid();
+    }
     DCHECK_NE(mojom::kInvalidInstanceID, id_);
   }
 
@@ -458,6 +460,7 @@
 
 Shell::~Shell() {
   TerminateShellConnections();
+  STLDeleteValues(&name_to_loader_);
   for (auto& runner : native_runners_)
     runner.reset();
 }
@@ -484,6 +487,14 @@
   Connect(std::move(params), std::move(client));
 
   return request;
+}
+
+void Shell::SetLoaderForName(std::unique_ptr<Loader> loader,
+                             const std::string& name) {
+  auto it = name_to_loader_.find(name);
+  if (it != name_to_loader_.end())
+    delete it->second;
+  name_to_loader_[name] = loader.release();
 }
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -726,22 +737,42 @@
   } else {
     // Otherwise we create a new ShellClient pipe.
     mojom::ShellClientRequest request = GetProxy(&client);
-    CHECK(!result->package_url.is_null() && !result->capabilities.is_null());
-
-    if (target.name() != result->resolved_name) {
+    if (LoadWithLoader(target, &request)) {
       instance->StartWithClient(std::move(client));
-      Identity factory(result->resolved_name, target.user_id(),
-                       instance_name);
-      CreateShellClientWithFactory(factory, target.name(),
-                                   std::move(request));
     } else {
-      instance->StartWithFilePath(
-          mojo::util::UrlToFilePath(result->package_url.To<GURL>()));
+      CHECK(!result->package_url.is_null() && !result->capabilities.is_null());
+
+      if (target.name() != result->resolved_name) {
+        instance->StartWithClient(std::move(client));
+        Identity factory(result->resolved_name, target.user_id(),
+                         instance_name);
+        CreateShellClientWithFactory(factory, target.name(),
+                                     std::move(request));
+      } else {
+        instance->StartWithFilePath(
+            mojo::util::UrlToFilePath(result->package_url.To<GURL>()));
+      }
     }
   }
 
   // Now that the instance has a ShellClient, we can connect to it.
   instance->ConnectToClient(std::move(params));
+}
+
+bool Shell::LoadWithLoader(const Identity& target,
+                           mojom::ShellClientRequest* request) {
+  Loader* loader = GetLoaderForName(target.name());
+  if (!loader)
+    return false;
+  loader->Load(target.name(), std::move(*request));
+  return true;
+}
+
+Loader* Shell::GetLoaderForName(const std::string& name) {
+  auto name_it = name_to_loader_.find(name);
+  if (name_it != name_to_loader_.end())
+    return name_it->second;
+  return default_loader_.get();
 }
 
 base::WeakPtr<Shell> Shell::GetWeakPtr() {