Abort and reschedule if script is not ready during execution time

third_party/WebKit/Source/core/dom/ScriptLoader.cpp

Index: third_party/WebKit/Source/core/dom/ScriptLoader.cpp
diff --git a/third_party/WebKit/Source/core/dom/ScriptLoader.cpp b/third_party/WebKit/Source/core/dom/ScriptLoader.cpp
index 31c1d938deca8f883f86d70c94fe50df1e4631cb..1207c89de1e01ecc11acbb99eb6b712cff922476 100644
--- a/third_party/WebKit/Source/core/dom/ScriptLoader.cpp
+++ b/third_party/WebKit/Source/core/dom/ScriptLoader.cpp
@@ -890,6 +890,15 @@ void ScriptLoader::Execute() {
   DCHECK(!will_be_parser_executed_);
   DCHECK(async_exec_type_ != ScriptRunner::kNone);
   DCHECK(pending_script_->IsExternal());
+
+  // If revalidation occurs after the script is scheduled for execution,
+  // the script may not be ready at this point.
+  // Abort execution and reschedule when the script is ready again.
+  if (!pending_script_->IsReady()) {
+    pending_script_->WatchForLoad(this);
+    return;
+  }
+
   bool error_occurred = false;
   Script* script = pending_script_->GetSource(KURL(), error_occurred);
   const bool wasCanceled = pending_script_->WasCanceled();