Revert of Streams: Remove isTerminating() calls

third_party/WebKit/Source/bindings/core/v8/WorkerOrWorkletScriptController.h

Index: third_party/WebKit/Source/bindings/core/v8/WorkerOrWorkletScriptController.h
diff --git a/third_party/WebKit/Source/bindings/core/v8/WorkerOrWorkletScriptController.h b/third_party/WebKit/Source/bindings/core/v8/WorkerOrWorkletScriptController.h
index 4ea92e4a76b3c06172b01c59bda673e104b5ad5b..1c6d97a0035a194513be3d270de72c9a391b0ac6 100644
--- a/third_party/WebKit/Source/bindings/core/v8/WorkerOrWorkletScriptController.h
+++ b/third_party/WebKit/Source/bindings/core/v8/WorkerOrWorkletScriptController.h
@@ -37,6 +37,7 @@
 #include "bindings/core/v8/V8CacheOptions.h"
 #include "core/CoreExport.h"
 #include "wtf/Allocator.h"
+#include "wtf/ThreadingPrimitives.h"
 #include "wtf/text/TextPosition.h"
 #include <v8.h>
 
@@ -56,15 +57,23 @@
     void dispose();
 
     bool isExecutionForbidden() const;
+    bool isExecutionTerminating() const;
 
     // Returns true if the evaluation completed with no uncaught exception.
     bool evaluate(const ScriptSourceCode&, ErrorEvent** = nullptr, CachedMetadataHandler* = nullptr, V8CacheOptions = V8CacheOptionsDefault);
 
-    // Prevents future JavaScript execution.
+    // Prevents future JavaScript execution. See
+    // willScheduleExecutionTermination, isExecutionForbidden.
     void forbidExecution();
 
     // Used by WorkerThread:
     bool initializeContextIfNeeded();
+    // Async request to terminate future JavaScript execution on the worker
+    // thread. JavaScript evaluation exits with a non-continuable exception and
+    // WorkerOrWorkletScriptController calls forbidExecution to prevent further
+    // JavaScript execution. Use forbidExecution()/isExecutionForbidden() to
+    // guard against reentry into JavaScript.
+    void willScheduleExecutionTermination();
 
     // Used by WorkerGlobalScope:
     void rethrowExceptionFromImportedScript(ErrorEvent*, ExceptionState&);
@@ -101,6 +110,8 @@
     RefPtr<DOMWrapperWorld> m_world;
     String m_disableEvalPending;
     bool m_executionForbidden;
+    bool m_executionScheduledToTerminate;
+    mutable Mutex m_scheduledTerminationMutex;
 
     RefPtr<RejectedPromises> m_rejectedPromises;