[proof-of-concept] SW thread independent of the main thread

third_party/WebKit/Source/core/workers/WorkerGlobalScope.cpp

Index: third_party/WebKit/Source/core/workers/WorkerGlobalScope.cpp
diff --git a/third_party/WebKit/Source/core/workers/WorkerGlobalScope.cpp b/third_party/WebKit/Source/core/workers/WorkerGlobalScope.cpp
index ba9f02c4601f906c33c04cf771a1238ea6ef7a84..65370c767c33eb695e382b8dded2db99f481dafa 100644
--- a/third_party/WebKit/Source/core/workers/WorkerGlobalScope.cpp
+++ b/third_party/WebKit/Source/core/workers/WorkerGlobalScope.cpp
@@ -54,6 +54,7 @@
 #include "core/workers/WorkerScriptLoader.h"
 #include "core/workers/WorkerThread.h"
 #include "platform/network/ContentSecurityPolicyParsers.h"
+#include "platform/TraceEvent.h"
 #include "platform/weborigin/KURL.h"
 #include "platform/weborigin/SecurityOrigin.h"
 #include "public/platform/Platform.h"
@@ -181,6 +182,7 @@ void WorkerGlobalScope::close()
 
 void WorkerGlobalScope::importScripts(const Vector<String>& urls, ExceptionState& exceptionState)
 {
+    TRACE_EVENT0("ServiceWorker", "WorkerGlobalScope::importScripts");
     DCHECK(contentSecurityPolicy());
     DCHECK(getExecutionContext());
 
@@ -203,7 +205,10 @@ void WorkerGlobalScope::importScripts(const Vector<String>& urls, ExceptionState
     for (const KURL& completeURL : completedURLs) {
         RefPtr<WorkerScriptLoader> scriptLoader(WorkerScriptLoader::create());
         scriptLoader->setRequestContext(WebURLRequest::RequestContextScript);
-        scriptLoader->loadSynchronously(executionContext, completeURL, AllowCrossOriginRequests, executionContext.securityContext().addressSpace());
+        {
+            TRACE_EVENT0("ServiceWorker", "WorkerGlobalScope::importScripts::loadSynchronously");
+            scriptLoader->loadSynchronously(executionContext, completeURL, AllowCrossOriginRequests, executionContext.securityContext().addressSpace());
+        }
 
         // If the fetching attempt failed, throw a NetworkError exception and
         // abort all these steps.
@@ -218,7 +223,10 @@ void WorkerGlobalScope::importScripts(const Vector<String>& urls, ExceptionState
         ErrorEvent* errorEvent = nullptr;
         std::unique_ptr<Vector<char>> cachedMetaData(scriptLoader->releaseCachedMetadata());
         CachedMetadataHandler* handler(createWorkerScriptCachedMetadataHandler(completeURL, cachedMetaData.get()));
-        m_scriptController->evaluate(ScriptSourceCode(scriptLoader->script(), scriptLoader->responseURL()), &errorEvent, handler, m_v8CacheOptions);
+        {
+            TRACE_EVENT0("ServiceWorker", "WorkerGlobalScope::importScripts::evaluate");
+            m_scriptController->evaluate(ScriptSourceCode(scriptLoader->script(), scriptLoader->responseURL()), &errorEvent, handler, m_v8CacheOptions);
+        }
         if (errorEvent) {
             m_scriptController->rethrowExceptionFromImportedScript(errorEvent, exceptionState);
             return;