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

third_party/WebKit/Source/core/streams/ReadableStreamOperations.cpp

Index: third_party/WebKit/Source/core/streams/ReadableStreamOperations.cpp
diff --git a/third_party/WebKit/Source/core/streams/ReadableStreamOperations.cpp b/third_party/WebKit/Source/core/streams/ReadableStreamOperations.cpp
index 1ba92208d9659bf4da755587bdc03aac0f592a8f..99fc1cb5e9af7ec79d4af1283a5e4a9deb5799d6 100644
--- a/third_party/WebKit/Source/core/streams/ReadableStreamOperations.cpp
+++ b/third_party/WebKit/Source/core/streams/ReadableStreamOperations.cpp
@@ -9,6 +9,7 @@
 #include "bindings/core/v8/V8ScriptRunner.h"
 #include "core/streams/UnderlyingSourceBase.h"
 #include "platform/bindings/ScriptState.h"
+#include "platform/instrumentation/tracing/TraceEvent.h"
 
 namespace blink {
 
@@ -16,6 +17,8 @@ ScriptValue ReadableStreamOperations::CreateReadableStream(
     ScriptState* script_state,
     UnderlyingSourceBase* underlying_source,
     ScriptValue strategy) {
+  TRACE_EVENT0("ServiceWorker",
+               "ReadableStreamOperations::CreateReadableStream");
   ScriptState::Scope scope(script_state);
 
   v8::Local<v8::Value> js_underlying_source =
@@ -31,6 +34,8 @@ ScriptValue ReadableStreamOperations::CreateReadableStream(
 ScriptValue ReadableStreamOperations::CreateCountQueuingStrategy(
     ScriptState* script_state,
     size_t high_water_mark) {
+  TRACE_EVENT0("ServiceWorker",
+               "ReadableStreamOperations::CreateCountQueuingStrategy");
   ScriptState::Scope scope(script_state);
 
   v8::Local<v8::Value> args[] = {