[mojo-edk] Add MojoWatch and MojoCancelWatch APIs

mojo/edk/system/dispatcher.cc

Index: mojo/edk/system/dispatcher.cc
diff --git a/mojo/edk/system/dispatcher.cc b/mojo/edk/system/dispatcher.cc
index d475ef6fa0da4bafbe49c5bd4de930f24544c419..2db7ed06d3914405a1331416f445a66a64ebe9b5 100644
--- a/mojo/edk/system/dispatcher.cc
+++ b/mojo/edk/system/dispatcher.cc
@@ -15,15 +15,38 @@
 namespace mojo {
 namespace edk {
 
+Dispatcher::RequestContext::RequestContext() {}
+
+Dispatcher::RequestContext::~RequestContext() {
+  for (const auto& finalizer : finalizers_.container())
+    finalizer.Run();
+}
+
+void Dispatcher::RequestContext::AddFinalizer(const base::Closure& callback) {
+  finalizers_->push_back(callback);
+}
+
 Dispatcher::DispatcherInTransit::DispatcherInTransit() {}
 
 Dispatcher::DispatcherInTransit::~DispatcherInTransit() {}
 
+MojoResult Dispatcher::Watch(MojoHandleSignals signals,
+                             const WatchCallback& callback,
+                             uintptr_t context,
+                             RequestContext* request_context) {
+  return MOJO_RESULT_INVALID_ARGUMENT;
+}
+
+MojoResult Dispatcher::CancelWatch(uintptr_t context) {
+  return MOJO_RESULT_INVALID_ARGUMENT;
+}
+
 MojoResult Dispatcher::WriteMessage(const void* bytes,
                                     uint32_t num_bytes,
                                     const DispatcherInTransit* dispatchers,
                                     uint32_t num_dispatchers,
-                                    MojoWriteMessageFlags flags) {
+                                    MojoWriteMessageFlags flags,
+                                    RequestContext* request_context) {
   return MOJO_RESULT_INVALID_ARGUMENT;
 }
 
@@ -31,7 +54,8 @@ MojoResult Dispatcher::ReadMessage(void* bytes,
                                    uint32_t* num_bytes,
                                    MojoHandle* handles,
                                    uint32_t* num_handles,
-                                   MojoReadMessageFlags flags) {
+                                   MojoReadMessageFlags flags,
+                                   RequestContext* request_context) {
   return MOJO_RESULT_INVALID_ARGUMENT;
 }
 
@@ -131,11 +155,11 @@ bool Dispatcher::EndSerialize(void* destination,
   return true;
 }
 
-bool Dispatcher::BeginTransit() { return true; }
+bool Dispatcher::BeginTransit(RequestContext* request_context) { return true; }
 
-void Dispatcher::CompleteTransitAndClose() {}
+void Dispatcher::CompleteTransitAndClose(RequestContext* request_context) {}
 
-void Dispatcher::CancelTransit() {}
+void Dispatcher::CancelTransit(RequestContext* request_context) {}
 
 // static
 scoped_refptr<Dispatcher> Dispatcher::Deserialize(