Gather trace data by waiting on handles with a fixed timeout

services/tracing/collector_impl.cc

Index: services/tracing/collector_impl.cc
diff --git a/services/tracing/collector_impl.cc b/services/tracing/collector_impl.cc
new file mode 100644
index 0000000000000000000000000000000000000000..6ce02e27b3cfa93e26ff79d1614406892c0f8ef6
--- /dev/null
+++ b/services/tracing/collector_impl.cc
@@ -0,0 +1,29 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "services/tracing/collector_impl.h"
+
+namespace tracing {
+
+CollectorImpl::CollectorImpl(mojo::InterfaceRequest<TraceDataCollector> request,
+                             TraceDataSink* sink)
+    : sink_(sink), binding_(this, request.Pass()) {
+}
+
+CollectorImpl::~CollectorImpl() {
+}
+
+void CollectorImpl::Read() {
+  binding_.WaitForIncomingMethodCall(MojoDeadline(0));

[viettrungluu, 2015/04/02 19:54:13]

Do you want to warn if this fails or anything like that?

[jamesr, 2015/04/06 22:31:04]

This could fail for legitimate reasons so I don't think we want to warn.  For
instance, we could notice that this pipe is readable but then find it's closed
when we try to read.  That just means the other side shut down and we may have
partial trace data but there's nothing wrong with that.

+}
+
+mojo::Handle CollectorImpl::RawHandleValue() const {
+  return binding_.handle();
+}
+
+void CollectorImpl::DataCollected(const mojo::String& json) {
+  sink_->AddChunk(json.To<std::string>());
+}
+
+}  // namespace tracing