Initial implementation of bindings and basic classes for worklets.

third_party/WebKit/Source/bindings/core/v8/V8Binding.cpp

Index: third_party/WebKit/Source/bindings/core/v8/V8Binding.cpp
diff --git a/third_party/WebKit/Source/bindings/core/v8/V8Binding.cpp b/third_party/WebKit/Source/bindings/core/v8/V8Binding.cpp
index d816d9b2a9353a8a749c8640f7e20a034d9c1352..4b8e6827c7aa62818d1e812053ad2e8da7c8651a 100644
--- a/third_party/WebKit/Source/bindings/core/v8/V8Binding.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/V8Binding.cpp
@@ -701,6 +701,10 @@ LocalDOMWindow* callingDOMWindow(v8::Isolate* isolate)
     return toLocalDOMWindow(toDOMWindow(context));
 }
 
+namespace {
+ExecutionContext* (*s_toExecutionContextForModules)(v8::Local<v8::Context>) = nullptr;
+}
+
 ExecutionContext* toExecutionContext(v8::Local<v8::Context> context)
 {
     if (context.IsEmpty())
@@ -712,8 +716,13 @@ ExecutionContext* toExecutionContext(v8::Local<v8::Context> context)
     v8::Local<v8::Object> workerWrapper = V8WorkerGlobalScope::findInstanceInPrototypeChain(global, context->GetIsolate());
     if (!workerWrapper.IsEmpty())
         return V8WorkerGlobalScope::toImpl(workerWrapper)->executionContext();
-    // FIXME: Is this line of code reachable?
-    return 0;
+    RELEASE_ASSERT(s_toExecutionContextForModules);

[haraken, 2016/01/12 00:38:49]

This is a performance-sensitive path, so let's use ASSERT not RELEASE_ASSERT.
Even if we don't have the ASSERT, the worst thing that can happen is just
(safely) crashing at the next line.

[ikilpatrick, 2016/01/12 04:11:24]

Done.

+    return (*s_toExecutionContextForModules)(context);
+}
+
+void registerToExecutionContextForModules(ExecutionContext* (*toExecutionContextForModules)(v8::Local<v8::Context>))
+{
+    s_toExecutionContextForModules = toExecutionContextForModules;
 }
 
 ExecutionContext* currentExecutionContext(v8::Isolate* isolate)
@@ -777,7 +786,7 @@ v8::Local<v8::Context> toV8Context(ExecutionContext* context, DOMWrapperWorld& w
         if (LocalFrame* frame = toDocument(context)->frame())
             return toV8Context(frame, world);
     } else if (context->isWorkerGlobalScope()) {
-        if (WorkerOrWorkletScriptController* script = toWorkerGlobalScope(context)->script()) {
+        if (WorkerOrWorkletScriptController* script = toWorkerOrWorkletGlobalScope(context)->script()) {
             if (script->scriptState()->contextIsValid())
                 return script->scriptState()->context();
         }