Worklet: Avoid import() on a detached frame

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

Index: third_party/WebKit/Source/core/workers/Worklet.cpp
diff --git a/third_party/WebKit/Source/core/workers/Worklet.cpp b/third_party/WebKit/Source/core/workers/Worklet.cpp
index fdafbedf116c18d95ad9d893c4b338f3c6eaafe3..1df2f5591d41f7561b216abb23b1eaf38c580f86 100644
--- a/third_party/WebKit/Source/core/workers/Worklet.cpp
+++ b/third_party/WebKit/Source/core/workers/Worklet.cpp
@@ -20,8 +20,11 @@ Worklet::Worklet(LocalFrame* frame)
 
 ScriptPromise Worklet::import(ScriptState* scriptState, const String& url) {
   DCHECK(isMainThread());
-  if (!isInitialized())
-    initialize();
+  if (!getExecutionContext()) {
+    return ScriptPromise::rejectWithDOMException(
+        scriptState, DOMException::create(InvalidStateError,
+                                          "This frame is already detached"));
+  }
 
   KURL scriptURL = getExecutionContext()->completeURL(url);
   if (!scriptURL.isValid()) {
@@ -30,6 +33,9 @@ ScriptPromise Worklet::import(ScriptState* scriptState, const String& url) {
         DOMException::create(SyntaxError, "'" + url + "' is not a valid URL."));
   }
 
+  if (!isInitialized())
+    initialize();
+
   ScriptPromiseResolver* resolver = ScriptPromiseResolver::create(scriptState);
   ScriptPromise promise = resolver->promise();