Gather trace data by waiting on handles with a fixed timeout

mojo/public/cpp/bindings/binding.h

Index: mojo/public/cpp/bindings/binding.h
diff --git a/mojo/public/cpp/bindings/binding.h b/mojo/public/cpp/bindings/binding.h
index 05a162e6518dfdecb84092389b27e4fab9ca3302..5894df41fb38cb9dc8e360f0ef9ff17497373c03 100644
--- a/mojo/public/cpp/bindings/binding.h
+++ b/mojo/public/cpp/bindings/binding.h
@@ -147,10 +147,12 @@ class Binding : public ErrorHandler {
   }
 
   // Blocks the calling thread until either a call arrives on the previously
-  // bound message pipe, or an error occurs.
-  bool WaitForIncomingMethodCall() {
+  // bound message pipe, the deadline is exceeded, or an error occurs. Returns
+  // true if a method was successfully read and dispatched.
+  bool WaitForIncomingMethodCall(
+      MojoDeadline deadline = MOJO_DEADLINE_INDEFINITE) {
     MOJO_DCHECK(internal_router_);
-    return internal_router_->WaitForIncomingMessage();
+    return internal_router_->WaitForIncomingMessage(deadline);
   }
 
   // Closes the message pipe that was previously bound. Put this object into a
@@ -194,6 +196,15 @@ class Binding : public ErrorHandler {
   // pipe has been bound to the implementation).
   bool is_bound() const { return !!internal_router_; }
 
+  // Returns the value of the handle currently bound to this Binding which can
+  // be used to make explicit Wait/WaitMany calls. Requires that the Binding be
+  // bound. Ownership of the handle is retained by the Binding, it is not
+  // transferred to the caller.
+  MessagePipeHandle handle() const {
+    MOJO_DCHECK(is_bound());
+    return internal_router_->handle();
+  }
+
   // Exposed for testing, should not generally be used.
   internal::Router* internal_router() { return internal_router_; }