Allow XHR timeout attribute to be overridden after send(), per spec

Source/core/loader/WorkerThreadableLoader.cpp

Index: Source/core/loader/WorkerThreadableLoader.cpp
diff --git a/Source/core/loader/WorkerThreadableLoader.cpp b/Source/core/loader/WorkerThreadableLoader.cpp
index 64e21d055f371f728a7203726a5ed40514fe8cc8..455aa91e0f8b8133f6a19f110b4229d1dc080a08 100644
--- a/Source/core/loader/WorkerThreadableLoader.cpp
+++ b/Source/core/loader/WorkerThreadableLoader.cpp
@@ -95,6 +95,11 @@ void WorkerThreadableLoader::loadResourceSynchronously(WorkerGlobalScope& worker
     clientBridgePtr->run();
 }
 
+void WorkerThreadableLoader::overrideTimeout(unsigned long timeoutMilliseconds)
+{
+    m_bridge.overrideTimeout(timeoutMilliseconds);
+}
+
 void WorkerThreadableLoader::cancel()
 {
     m_bridge.cancel();
@@ -152,6 +157,16 @@ void WorkerThreadableLoader::MainThreadBridge::destroy()
         createCallbackTask(&MainThreadBridge::mainThreadDestroy, AllowCrossThreadAccess(this)));
 }
 
+void WorkerThreadableLoader::MainThreadBridge::mainThreadOverrideTimeout(ExecutionContext* context, MainThreadBridge* thisPtr, unsigned long timeoutMilliseconds)
+{
+    ASSERT(isMainThread());
+    ASSERT_UNUSED(context, context->isDocument());
+
+    if (!thisPtr->m_mainThreadLoader)
+        return;
+    thisPtr->m_mainThreadLoader->overrideTimeout(timeoutMilliseconds);
+}
+
 void WorkerThreadableLoader::MainThreadBridge::mainThreadCancel(ExecutionContext* context, MainThreadBridge* thisPtr)
 {
     ASSERT(isMainThread());
@@ -163,6 +178,13 @@ void WorkerThreadableLoader::MainThreadBridge::mainThreadCancel(ExecutionContext
     thisPtr->m_mainThreadLoader = nullptr;
 }
 
+void WorkerThreadableLoader::MainThreadBridge::overrideTimeout(unsigned long timeoutMilliseconds)
+{
+    m_loaderProxy.postTaskToLoader(
+        createCallbackTask(&MainThreadBridge::mainThreadOverrideTimeout, AllowCrossThreadAccess(this),
+            timeoutMilliseconds));
+}
+
 void WorkerThreadableLoader::MainThreadBridge::cancel()
 {
     m_loaderProxy.postTaskToLoader(