Mojo: Cancel WaitingCallbacks when their HandleWrappers are closed.

mojo/bindings/js/handle.cc

Index: mojo/bindings/js/handle.cc
diff --git a/mojo/bindings/js/handle.cc b/mojo/bindings/js/handle.cc
index e1d0fb04b60c063466536c04f48502c7b1423179..5273adc9e0ff7ac13b1652777f6c036a5a34b54d 100644
--- a/mojo/bindings/js/handle.cc
+++ b/mojo/bindings/js/handle.cc
@@ -4,6 +4,8 @@
 
 #include "mojo/bindings/js/handle.h"
 
+#include "base/logging.h"
+
 namespace gin {
 
 gin::WrapperInfo HandleWrapper::kWrapperInfo = { gin::kEmbedderNativeGin };
@@ -13,6 +15,30 @@ HandleWrapper::HandleWrapper(MojoHandle handle)
 }
 
 HandleWrapper::~HandleWrapper() {
+  NotifyCloseObservers();
+}
+
+void HandleWrapper::Close() {
+  NotifyCloseObservers();
+  handle_.reset();
+}
+
+void HandleWrapper::AddCloseObserver(CloseObserver* observer) {
+  bool inserted = observers_.insert(observer).second;
+  DCHECK(inserted);
+}
+
+void HandleWrapper::RemoveCloseObserver(CloseObserver* observer) {
+  size_t removed = observers_.erase(observer);
+  DCHECK_EQ(removed, 1u);
+}
+
+void HandleWrapper::NotifyCloseObservers() {
+  for (std::set<CloseObserver*>::iterator it = observers_.begin();
+       it != observers_.end();) {
+    (*it++)->OnHandleClosed();

[abarth-chromium, 2014/09/03 05:21:55]

What if observers_ is modified during this iteration?

[Sam McNally, 2014/09/03 05:37:27]

Done.

+  }
+  observers_.clear();
 }
 
 v8::Handle<v8::Value> Converter<mojo::Handle>::ToV8(v8::Isolate* isolate,