Expose worklet on Window through attribute renderWorklet.

third_party/WebKit/Source/modules/worklet/WorkletGlobalScope.cpp

Index: third_party/WebKit/Source/modules/worklet/WorkletGlobalScope.cpp
diff --git a/third_party/WebKit/Source/modules/worklet/WorkletGlobalScope.cpp b/third_party/WebKit/Source/modules/worklet/WorkletGlobalScope.cpp
index e2ead6ea6739919f04dd404a478d92b0f0436cf2..15819a4a16dc0a95ab5071e3fa6d2207891a1f1c 100644
--- a/third_party/WebKit/Source/modules/worklet/WorkletGlobalScope.cpp
+++ b/third_party/WebKit/Source/modules/worklet/WorkletGlobalScope.cpp
@@ -11,13 +11,14 @@ namespace blink {
 // static
 PassRefPtrWillBeRawPtr<WorkletGlobalScope> WorkletGlobalScope::create(const KURL& url, const String& userAgent, v8::Isolate* isolate)
 {
-    return adoptRefWillBeNoop(new WorkletGlobalScope(url, userAgent, isolate));
+    RefPtrWillBeRawPtr<WorkletGlobalScope> workletGlobalScope = adoptRefWillBeNoop(new WorkletGlobalScope(url, userAgent, isolate));
+    workletGlobalScope->script()->initializeContextIfNeeded();

[ikilpatrick, 2016/01/14 19:31:57]

This was added here as within:
V8DOMWrapper::associateObjectWithWrapper (inside initializeContextIfNeeded())

there is an assert to check that the GlobalScope is adopted by something.

+    return workletGlobalScope.release();
 }
 
 WorkletGlobalScope::WorkletGlobalScope(const KURL& url, const String& userAgent, v8::Isolate* isolate)
     : m_script(WorkerOrWorkletScriptController::create(this, isolate))
 {
-    m_script->initializeContextIfNeeded();
 }
 
 WorkletGlobalScope::~WorkletGlobalScope()