Add TraceProviderRegistry and implementation in tracing service/application.

services/tracing/tracing_app.cc

 // 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/tracing_app.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "mojo/public/cpp/system/wait.h"
 
 namespace tracing {
 
 TracingApp::TracingApp() : collector_binding_(this), tracing_active_(false) {}
 
 TracingApp::~TracingApp() {}
 
 bool TracingApp::ConfigureIncomingConnection(
     mojo::ApplicationConnection* connection) {
   connection->AddService<TraceCollector>(this);
 
   // If someone connects to us they may want to use the TraceCollector
   // interface and/or they may want to expose themselves to be traced. Attempt
   // to connect to the TraceProvider interface to see if the application
   // connecting to us wants to be traced. They can refuse the connection or
   // close the pipe if not.
+  // TODO(vtl): Remove this once we remove the "wrong way" ServiceProvider.
   TraceProviderPtr provider_ptr;
   connection->ConnectToService(&provider_ptr);
-  if (tracing_active_) {
-    TraceRecorderPtr recorder_ptr;
-    recorder_impls_.push_back(
-        new TraceRecorderImpl(GetProxy(&recorder_ptr), sink_.get()));
-    provider_ptr->StartTracing(tracing_categories_, recorder_ptr.Pass());
-  }
-  provider_ptrs_.AddInterfacePtr(provider_ptr.Pass());
+  RegisterTraceProvider(provider_ptr.PassInterfaceHandle());
+
   return true;
 }
 
-// mojo::InterfaceFactory<TraceCollector> implementation.
 void TracingApp::Create(mojo::ApplicationConnection* connection,
                         mojo::InterfaceRequest<TraceCollector> request) {
   if (collector_binding_.is_bound()) {
     LOG(ERROR) << "Another application is already connected to tracing.";
     return;
   }
 
   collector_binding_.Bind(request.Pass());
 }
 
-// tracing::TraceCollector implementation.
+void TracingApp::Create(mojo::ApplicationConnection* connection,
+                        mojo::InterfaceRequest<TraceProviderRegistry> request) {
+  provider_registry_bindings_.AddBinding(this, request.Pass());

[jamesr, 2016/04/28 20:59:02]

at what point do we start saying std::move(request) instead of request.Pass() ?

+}
+
 void TracingApp::Start(mojo::ScopedDataPipeProducerHandle stream,
                        const mojo::String& categories) {
   tracing_categories_ = categories;
   sink_.reset(new TraceDataSink(stream.Pass()));
   provider_ptrs_.ForAllPtrs([categories, this](TraceProvider* controller) {
     TraceRecorderPtr ptr;
     recorder_impls_.push_back(
         new TraceRecorderImpl(GetProxy(&ptr), sink_.get()));
     controller->StartTracing(categories, ptr.Pass());
   });
@@ skipping 58 matching lines @@
         else if (satisfied & MOJO_HANDLE_SIGNAL_PEER_CLOSED)
           recorder_impls_.erase(recorder_impls_.begin() + index);
       }
       // Something happened so push back the timeout deadline.
       end = MojoGetTimeTicksNow() + kTimeToWaitMicros;
     }
   }
   AllDataCollected();
 }
 
+void TracingApp::RegisterTraceProvider(
+    mojo::InterfaceHandle<TraceProvider> trace_provider) {
+  auto provider_ptr = TraceProviderPtr::Create(trace_provider.Pass());
+  if (tracing_active_) {
+    TraceRecorderPtr recorder_ptr;
+    recorder_impls_.push_back(
+        new TraceRecorderImpl(GetProxy(&recorder_ptr), sink_.get()));
+    provider_ptr->StartTracing(tracing_categories_, recorder_ptr.Pass());
+  }
+  provider_ptrs_.AddInterfacePtr(provider_ptr.Pass());
+}
+
 void TracingApp::AllDataCollected() {
   recorder_impls_.clear();
   sink_.reset();
 }
 
 }  // namespace tracing