Revert of Move content's shell connections to the IO thread

services/shell/public/cpp/shell_connection.h

Index: services/shell/public/cpp/shell_connection.h
diff --git a/services/shell/public/cpp/shell_connection.h b/services/shell/public/cpp/shell_connection.h
index 9c1b6800dea718a63ff234ae406b03ecc7d9592b..8348a210c6bf7c14d8d0e60b1afbfd97c63ed7e0 100644
--- a/services/shell/public/cpp/shell_connection.h
+++ b/services/shell/public/cpp/shell_connection.h
@@ -11,14 +11,16 @@
 
 #include "base/callback.h"
 #include "base/macros.h"
+#include "base/memory/scoped_vector.h"
 #include "mojo/public/cpp/bindings/binding.h"
 #include "mojo/public/cpp/system/core.h"
-#include "services/shell/public/cpp/connector.h"
 #include "services/shell/public/cpp/service.h"
 #include "services/shell/public/interfaces/connector.mojom.h"
 #include "services/shell/public/interfaces/service.mojom.h"
 
 namespace shell {
+
+class Connector;
 
 // Encapsulates a connection to the Mojo Shell in two parts:
 // - a bound InterfacePtr to mojom::Shell, the primary mechanism
@@ -43,19 +45,21 @@
  public:
   // Creates a new ShellConnection bound to |request|. This connection may be
   // used immediately to make outgoing connections via connector().  Does not
-  // take ownership of |service|, which must remain valid for the lifetime of
-  // ShellConnection. If either |connector| or |connector_request| is non-null
-  // both must be non-null. If both are null, the connection will create its own
-  // Connector and request to pass to the shell on initialization.
-  ShellConnection(shell::Service* service,
-                  mojom::ServiceRequest request,
-                  std::unique_ptr<Connector> connector = nullptr,
-                  mojom::ConnectorRequest connector_request = nullptr);
+  // take ownership of |client|, which must remain valid for the lifetime of
+  // ShellConnection.
+  ShellConnection(shell::Service* client,
+                  mojom::ServiceRequest request);
 
   ~ShellConnection() override;
 
   Connector* connector() { return connector_.get(); }
   const Identity& identity() { return identity_; }
+
+  // TODO(rockot): Remove this. http://crbug.com/594852.
+  void set_initialize_handler(const base::Closure& callback);
+
+  // TODO(rockot): Remove this once we get rid of app tests.
+  void SetAppTestConnectorForTesting(mojom::ConnectorPtr connector);
 
   // Specify a function to be called when the connection to the shell is lost.
   // Note that if connection has already been lost, then |closure| is called
@@ -81,12 +85,12 @@
 
   // We track the lifetime of incoming connection registries as it more
   // convenient for the client.
-  std::vector<std::unique_ptr<Connection>> incoming_connections_;
+  ScopedVector<Connection> incoming_connections_;
 
   // A pending Connector request which will eventually be passed to the shell.
   mojom::ConnectorRequest pending_connector_request_;
 
-  shell::Service* service_;
+  shell::Service* client_;
   mojo::Binding<mojom::Service> binding_;
   std::unique_ptr<Connector> connector_;
   shell::Identity identity_;