Make ThreadableLoader class to use references

Source/core/xml/XMLHttpRequest.cpp

Index: Source/core/xml/XMLHttpRequest.cpp
diff --git a/Source/core/xml/XMLHttpRequest.cpp b/Source/core/xml/XMLHttpRequest.cpp
index c0cbccdf858e8a621e52182c9d9d443af359848a..fb251ca68baa9724331f36e96ad6d5bb695c740d 100644
--- a/Source/core/xml/XMLHttpRequest.cpp
+++ b/Source/core/xml/XMLHttpRequest.cpp
@@ -794,11 +794,14 @@ void XMLHttpRequest::createRequest(ExceptionState& exceptionState)
     // added after the request is started.
     m_uploadEventsAllowed = m_sameOriginRequest || uploadEvents || !isSimpleCrossOriginAccessRequest(m_method, m_requestHeaders);
 
+    ASSERT(executionContext());
+    ExecutionContext& executionContext = *this->executionContext();
+
     ResourceRequest request(m_url);
     request.setHTTPMethod(m_method);
     request.setTargetType(ResourceRequest::TargetIsXHR);
 
-    InspectorInstrumentation::willLoadXHR(executionContext(), this, this, m_method, m_url, m_async, m_requestEntityBody ? m_requestEntityBody->deepCopy() : nullptr, m_requestHeaders, m_includeCredentials);
+    InspectorInstrumentation::willLoadXHR(&executionContext, this, this, m_method, m_url, m_async, m_requestEntityBody ? m_requestEntityBody->deepCopy() : nullptr, m_requestHeaders, m_includeCredentials);
 
     if (m_requestEntityBody) {
         ASSERT(m_method != "GET");
@@ -817,7 +820,7 @@ void XMLHttpRequest::createRequest(ExceptionState& exceptionState)
     options.crossOriginRequestPolicy = UseAccessControl;
     options.securityOrigin = securityOrigin();
     options.initiator = FetchInitiatorTypeNames::xmlhttprequest;
-    options.contentSecurityPolicyEnforcement = ContentSecurityPolicy::shouldBypassMainWorld(executionContext()) ? DoNotEnforceContentSecurityPolicy : EnforceConnectSrcDirective;
+    options.contentSecurityPolicyEnforcement = ContentSecurityPolicy::shouldBypassMainWorld(&executionContext) ? DoNotEnforceContentSecurityPolicy : EnforceConnectSrcDirective;
     // TODO(tsepez): Specify TreatAsActiveContent per http://crbug.com/305303.
     options.mixedContentBlockingTreatment = TreatAsPassiveContent;
     options.timeoutMilliseconds = m_timeoutMilliseconds;
@@ -834,7 +837,7 @@ void XMLHttpRequest::createRequest(ExceptionState& exceptionState)
         // FIXME: Maybe we need to be able to send XMLHttpRequests from onunload, <http://bugs.webkit.org/show_bug.cgi?id=10904>.
         // FIXME: Maybe create() can return null for other reasons too?
         ASSERT(!m_loader);
-        m_loader = ThreadableLoader::create(executionContext(), this, request, options);
+        m_loader = ThreadableLoader::create(executionContext, this, request, options);
         if (m_loader) {
             // Neither this object nor the JavaScript wrapper should be deleted while
             // a request is in progress because we need to keep the listeners alive,
@@ -842,7 +845,7 @@ void XMLHttpRequest::createRequest(ExceptionState& exceptionState)
             setPendingActivity(this);
         }
     } else {
-        ThreadableLoader::loadResourceSynchronously(executionContext(), request, *this, options);
+        ThreadableLoader::loadResourceSynchronously(executionContext, request, *this, options);
     }
 
     if (!m_exceptionCode && m_error)