Plumbs through android supplying multipe touch points

services/native_viewport/native_viewport_impl.h

Index: services/native_viewport/native_viewport_impl.h
diff --git a/services/native_viewport/native_viewport_impl.h b/services/native_viewport/native_viewport_impl.h
index 4e778009158c9be3113033bfdc7a8fea8a9a3bae..ebced45d340d948aec2b53bb986383b6eb7e3f68 100644
--- a/services/native_viewport/native_viewport_impl.h
+++ b/services/native_viewport/native_viewport_impl.h
@@ -5,6 +5,8 @@
 #ifndef SERVICES_NATIVE_VIEWPORT_NATIVE_VIEWPORT_IMPL_H_
 #define SERVICES_NATIVE_VIEWPORT_NATIVE_VIEWPORT_IMPL_H_
 
+#include <set>
+
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "mojo/public/cpp/bindings/strong_binding.h"
@@ -59,21 +61,31 @@ class NativeViewportImpl : public mojo::NativeViewport,
   // mojo::ErrorHandler implementation.
   void OnConnectionError() override;
 
-  void AckEvent();
-
  private:
+  // Used by AckEvent; see it for details.
+  struct PointerId {
+    int32 id;

[qsr, 2015/03/24 08:20:22]

I am missing something, but why do you need this object? Can't you just pass
ints? Or are you planning to need more data in the future?

[sky, 2015/03/24 13:18:21]

I did this as I thought it a bit mysterious to take an int*. It isn't clear if
it's an array, or just one. But I changed it.

+  };
+
+  // Callback when the dispatcher has processed a message we're waiting on
+  // an ack from. |id->id| identifies the pointer the message was associated
+  // with. Receiver does not own supplied value (its owned by the callback).
+  void AckEvent(PointerId* id);
+
   bool is_headless_;
   scoped_ptr<PlatformViewport> platform_viewport_;
   OnscreenContextProvider context_provider_;
   bool sent_metrics_;
   mojo::ViewportMetricsPtr metrics_;
-  bool waiting_for_event_ack_;
   CreateCallback create_callback_;
   RequestMetricsCallback metrics_callback_;
   mojo::NativeViewportEventDispatcherPtr event_dispatcher_;
   mojo::Binding<mojo::NativeViewport> binding_;
   base::WeakPtrFactory<NativeViewportImpl> weak_factory_;
 
+  // Set of pointer_ids we've sent a move to and are waiting on an ack.
+  std::set<int32> pointers_waiting_on_ack_;
+
   DISALLOW_COPY_AND_ASSIGN(NativeViewportImpl);
 };