[Not for review] Add traces for crbug.com/726626

third_party/WebKit/Source/modules/fetch/BodyStreamBuffer.cpp

 // Copyright 2014 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 "modules/fetch/BodyStreamBuffer.h"
 
 #include <memory>
 #include "bindings/core/v8/ExceptionState.h"
 #include "core/dom/DOMArrayBuffer.h"
 #include "core/dom/DOMTypedArray.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/dom/ExecutionContext.h"
 #include "core/streams/ReadableStreamController.h"
 #include "core/streams/ReadableStreamOperations.h"
 #include "modules/fetch/Body.h"
 #include "modules/fetch/ReadableStreamBytesConsumer.h"
 #include "platform/bindings/ScriptState.h"
 #include "platform/bindings/V8PrivateProperty.h"
 #include "platform/bindings/V8ThrowException.h"
 #include "platform/blob/BlobData.h"
+#include "platform/instrumentation/tracing/TraceEvent.h"
 #include "platform/network/EncodedFormData.h"
 
 namespace blink {
 
 class BodyStreamBuffer::LoaderClient final
     : public GarbageCollectedFinalized<LoaderClient>,
       public ContextLifecycleObserver,
       public FetchDataLoader::Client {
   WTF_MAKE_NONCOPYABLE(LoaderClient);
   USING_GARBAGE_COLLECTED_MIXIN(LoaderClient);
@@ skipping 55 matching lines @@
   Member<BodyStreamBuffer> buffer_;
   Member<FetchDataLoader::Client> client_;
 };
 
 BodyStreamBuffer::BodyStreamBuffer(ScriptState* script_state,
                                    BytesConsumer* consumer)
     : UnderlyingSourceBase(script_state),
       script_state_(script_state),
       consumer_(consumer),
       made_from_readable_stream_(false) {
+  TRACE_EVENT0("ServiceWorker", "BodyStreamBuffer::BodyStreamBuffer");
   v8::Local<v8::Value> body_value = ToV8(this, script_state);
   DCHECK(!body_value.IsEmpty());
   DCHECK(body_value->IsObject());
   v8::Local<v8::Object> body = body_value.As<v8::Object>();
 
-  ScriptValue readable_stream = ReadableStreamOperations::CreateReadableStream(
-      script_state, this,
-      ReadableStreamOperations::CreateCountQueuingStrategy(script_state, 0));
+  ScriptValue readable_stream;
+  {
+    TRACE_EVENT0("ServiceWorker",
+                 "BodyStreamBuffer::BodyStreamBuffer CreateReadableStream");
+    readable_stream = ReadableStreamOperations::CreateReadableStream(
+        script_state, this,
+        ReadableStreamOperations::CreateCountQueuingStrategy(script_state, 0));
+  }
   DCHECK(!readable_stream.IsEmpty());
-  V8PrivateProperty::GetInternalBodyStream(script_state->GetIsolate())
-      .Set(body, readable_stream.V8Value());
+  {
+    TRACE_EVENT0("ServiceWorker",
+                 "BodyStreamBuffer::BodyStreamBuffer GetInternalBodyStream");
+    V8PrivateProperty::GetInternalBodyStream(script_state->GetIsolate())
+        .Set(body, readable_stream.V8Value());
+  }
   consumer_->SetClient(this);
   OnStateChange();
 }
 
 BodyStreamBuffer::BodyStreamBuffer(ScriptState* script_state,
                                    ScriptValue stream)
     : UnderlyingSourceBase(script_state),
       script_state_(script_state),
       made_from_readable_stream_(true) {
   DCHECK(ReadableStreamOperations::IsReadableStream(script_state, stream));
@@ skipping 277 matching lines @@
   }
   if (is_errored)
     return BytesConsumer::CreateErrored(BytesConsumer::Error("error"));
 
   DCHECK(consumer);
   consumer->ClearClient();
   return consumer;
 }
 
 }  // namespace blink