Mojo: Cancel WaitingCallbacks when their HandleWrappers are closed.

mojo/bindings/js/waiting_callback.h

Index: mojo/bindings/js/waiting_callback.h
diff --git a/mojo/bindings/js/waiting_callback.h b/mojo/bindings/js/waiting_callback.h
index 973a500cdf0919731c60f03738b086ba7ca7473a..cdb62d53df8a31556997c8d4a6ceb78455d0f45b 100644
--- a/mojo/bindings/js/waiting_callback.h
+++ b/mojo/bindings/js/waiting_callback.h
@@ -8,13 +8,15 @@
 #include "gin/handle.h"
 #include "gin/runner.h"
 #include "gin/wrappable.h"
+#include "mojo/bindings/js/handle.h"
 #include "mojo/public/c/environment/async_waiter.h"
 #include "mojo/public/cpp/system/core.h"
 
 namespace mojo {
 namespace js {
 
-class WaitingCallback : public gin::Wrappable<WaitingCallback> {
+class WaitingCallback : public gin::Wrappable<WaitingCallback>,
+                        public gin::HandleWrapper::CloseObserver {
  public:
   static gin::WrapperInfo kWrapperInfo;
 
@@ -22,7 +24,7 @@ class WaitingCallback : public gin::Wrappable<WaitingCallback> {
   static gin::Handle<WaitingCallback> Create(
       v8::Isolate* isolate,
       v8::Handle<v8::Function> callback,
-      mojo::Handle handle,
+      gin::Handle<gin::HandleWrapper> handle_wrapper,
       MojoHandleSignals signals);
 
   // Cancels the callback. Does nothing if a callback is not pending. This is
@@ -31,7 +33,9 @@ class WaitingCallback : public gin::Wrappable<WaitingCallback> {
   void Cancel();
 
  private:
-  WaitingCallback(v8::Isolate* isolate, v8::Handle<v8::Function> callback);
+  WaitingCallback(v8::Isolate* isolate,
+                  v8::Handle<v8::Function> callback,
+                  gin::Handle<gin::HandleWrapper> handle_wrapper);
   virtual ~WaitingCallback();
 
   // Callback from MojoAsyncWaiter. |closure| is the WaitingCallback.
@@ -40,9 +44,15 @@ class WaitingCallback : public gin::Wrappable<WaitingCallback> {
   // Invoked from CallOnHandleReady() (CallOnHandleReady() must be static).
   void OnHandleReady(MojoResult result);
 
+  // Invoked by the HandleWrapper if the handle is closed while this wait is
+  // still in progress.
+  virtual void OnHandleClosed() OVERRIDE;
+
   base::WeakPtr<gin::Runner> runner_;
   MojoAsyncWaitID wait_id_;
 
+  gin::HandleWrapper* handle_wrapper_;
+
   DISALLOW_COPY_AND_ASSIGN(WaitingCallback);
 };