Move content's shell connections to the IO thread

content/public/common/mojo_shell_connection.h

Index: content/public/common/mojo_shell_connection.h
diff --git a/content/public/common/mojo_shell_connection.h b/content/public/common/mojo_shell_connection.h
index 1fbe2439a4ad789882fe00729c2cebe94c9446dc..68eca44f07ba7b447de56d3538379d0d8d0703f0 100644
--- a/content/public/common/mojo_shell_connection.h
+++ b/content/public/common/mojo_shell_connection.h
@@ -8,6 +8,7 @@
 #include <memory>
 
 #include "base/callback_forward.h"
+#include "base/sequenced_task_runner.h"
 #include "content/common/content_export.h"
 #include "content/public/common/mojo_application_info.h"
 #include "services/shell/public/cpp/identity.h"
@@ -35,6 +36,8 @@ class CONTENT_EXPORT MojoShellConnection {
   using ShellClientRequestHandler =
       base::Callback<void(shell::mojom::ShellClientRequest)>;
   using Factory = base::Callback<std::unique_ptr<MojoShellConnection>(void)>;
+  using ConnectionFilter =
+      base::Callback<bool(shell::Connection*, shell::Connector*)>;
 
   // Stores an instance of |connection| in TLS for the current process. Must be
   // called on the thread the connection was created on.
@@ -55,13 +58,15 @@ class CONTENT_EXPORT MojoShellConnection {
   // called before the MojoShellConnection has been created.
   static void SetFactoryForTest(Factory* factory);
 
-  // Creates a MojoShellConnection from |request|.
+  // Creates a MojoShellConnection from |request|. The connection bind
+  // its interfaces and accept new connections on |io_task_runner| only.
   static std::unique_ptr<MojoShellConnection> Create(
-      shell::mojom::ShellClientRequest request);
+      shell::mojom::ShellClientRequest request,
+      scoped_refptr<base::SequencedTaskRunner> io_task_runner);
 
-  // Returns the bound shell::ShellConnection object.
-  // TODO(rockot): remove.
-  virtual shell::ShellConnection* GetShellConnection() = 0;
+  // Sets a closure to be invoked once the connection receives an Initialize()
+  // request from the shell.
+  virtual void SetInitializeHandler(const base::Closure& handler) = 0;
 
   // Returns the shell::Connector received via this connection's ShellClient
   // implementation. Use this to initiate connections as this object's Identity.
@@ -76,13 +81,10 @@ class CONTENT_EXPORT MojoShellConnection {
   // run immediately before returning from this function.
   virtual void SetConnectionLostClosure(const base::Closure& closure) = 0;
 
-  // Allows the caller to expose interfaces to the caller using the identity of
-  // this object's ShellClient. As distinct from AddEmbeddedService() and
-  // AddShellClientRequestHandler() which specify unique identities for the
-  // registered services.
-  virtual void AddEmbeddedShellClient(
-      std::unique_ptr<shell::ShellClient> shell_client) = 0;
-  virtual void AddEmbeddedShellClient(shell::ShellClient* shell_client) = 0;
+  // Allows the caller to filter inbound connections and/or expose interfaces
+  // on them. Note that ConnectionFilters are always invoked on the
+  // |io_task_runner| (see Create above.)
+  virtual void AddConnectionFilter(const ConnectionFilter& filter) = 0;
 
   // Adds an embedded service to this connection's ShellClientFactory.
   // |info| provides details on how to construct new instances of the