Convert NaCl renderer-loader messages to mojo.

components/nacl/loader/nacl_trusted_listener.cc

Index: components/nacl/loader/nacl_trusted_listener.cc
diff --git a/components/nacl/loader/nacl_trusted_listener.cc b/components/nacl/loader/nacl_trusted_listener.cc
index df8fc200c14b78b5b5d7ef904414b338d541add3..d549ea643868db42601b2adbc4782cbe1e470a32 100644
--- a/components/nacl/loader/nacl_trusted_listener.cc
+++ b/components/nacl/loader/nacl_trusted_listener.cc
@@ -6,52 +6,40 @@
 
 #include "base/single_thread_task_runner.h"
 #include "build/build_config.h"
-#include "ipc/message_filter.h"
+#include "mojo/public/cpp/bindings/strong_binding.h"
 #include "native_client/src/public/chrome_main.h"
 
 namespace {
 
-// The OnChannelError() event must be processed in a MessageFilter so it can
-// be handled on the IO thread.  The main thread used by NaClListener is busy
-// in NaClChromeMainAppStart(), so it can't be used for servicing messages.
-class EOFMessageFilter : public IPC::MessageFilter {
- public:
-  void OnChannelError() override {
-    // The renderer process dropped its connection to this process (the NaCl
-    // loader process), either because the <embed> element was removed
-    // (perhaps implicitly if the tab was closed) or because the renderer
-    // crashed.  The NaCl loader process should therefore exit.
-    //
-    // For SFI NaCl, trusted code does this exit voluntarily, but untrusted
-    // code cannot disable it.  However, for Non-SFI NaCl, the following exit
-    // call could be disabled by untrusted code.
-    NaClExit(0);
-  }
- private:
-  ~EOFMessageFilter() override {}
-};
-
+void CreateExitControl(nacl::mojom::NaClExitControlRequest request) {
+  // If the binding disconnects, the renderer process dropped its connection to
+  // this process (the NaCl loader process), either because the <embed> element
+  // was removed (perhaps implicitly if the tab was closed) or because the
+  // renderer crashed.  The NaCl loader process should therefore exit.
+  //
+  // For SFI NaCl, trusted code does this exit voluntarily, but untrusted
+  // code cannot disable it.  However, for Non-SFI NaCl, the following exit
+  // call could be disabled by untrusted code.
+  mojo::MakeStrongBinding<nacl::mojom::NaClExitControl,
+                          nacl::mojom::NaClExitControl>(nullptr,
+                                                        std::move(request))
+      ->set_connection_error_handler(base::Bind(&NaClExit, 0));

[dcheng, 2016/12/20 06:49:54]

This feels like an abuse of mojo::MakeStrongBinding. At some point, I still hope
that we can land some variant of https://codereview.chromium.org/2515873003/.

[Sam McNally, 2016/12/20 10:02:19]

Yes, but it was so simple. Added a class for the binding to own.

 }
 
-NaClTrustedListener::NaClTrustedListener(
-    const IPC::ChannelHandle& handle,
-    base::SingleThreadTaskRunner* ipc_task_runner,
-    base::WaitableEvent* shutdown_event)
-    : channel_handle_(handle) {
-  channel_ =
-      IPC::SyncChannel::Create(handle, IPC::Channel::MODE_SERVER, this,
-                               ipc_task_runner, true, /* create_channel_now */
-                               shutdown_event);
-  channel_->AddFilter(new EOFMessageFilter());
-}
+}  // namespace
 
-NaClTrustedListener::~NaClTrustedListener() {
-}
-
-bool NaClTrustedListener::OnMessageReceived(const IPC::Message& msg) {
-  return false;
+NaClTrustedListener::NaClTrustedListener(
+    nacl::mojom::NaClRendererHostPtr renderer_host,
+    base::SingleThreadTaskRunner* io_task_runner)
+    : renderer_host_(std::move(renderer_host)) {
+  nacl::mojom::NaClExitControlPtr exit_control;
+  // The exit control binding must run on the IO thread. The main thread used
+  // by NaClListener is busy in NaClChromeMainAppStart(), so it can't be used
+  // for servicing messages.
+  io_task_runner->PostTask(
+      FROM_HERE, base::Bind(&CreateExitControl,
+                            base::Passed(mojo::GetProxy(&exit_control))));
+  renderer_host_->ProvideExitControl(std::move(exit_control));
 }
 
-bool NaClTrustedListener::Send(IPC::Message* msg) {
-  return channel_->Send(msg);
-}
+NaClTrustedListener::~NaClTrustedListener() = default;