[debugger] expose side-effect free evaluate to inspector.

src/inspector/v8-debugger-agent-impl.cc

Index: src/inspector/v8-debugger-agent-impl.cc
diff --git a/src/inspector/v8-debugger-agent-impl.cc b/src/inspector/v8-debugger-agent-impl.cc
index 664c2ed095a0545d2ee655c3b15178e21e056f3f..d4e75abee5887f9c16b1e38c7b6a1908eba35c82 100644
--- a/src/inspector/v8-debugger-agent-impl.cc
+++ b/src/inspector/v8-debugger-agent-impl.cc
@@ -690,8 +690,8 @@ void V8DebuggerAgentImpl::setPauseOnExceptionsImpl(int pauseState) {
 Response V8DebuggerAgentImpl::evaluateOnCallFrame(
     const String16& callFrameId, const String16& expression,
     Maybe<String16> objectGroup, Maybe<bool> includeCommandLineAPI,
-    Maybe<bool> silent, Maybe<bool> returnByValue, Maybe<bool> generatePreview,
-    std::unique_ptr<RemoteObject>* result,
+    Maybe<bool> allowSideEffect, Maybe<bool> silent, Maybe<bool> returnByValue,
+    Maybe<bool> generatePreview, std::unique_ptr<RemoteObject>* result,
     Maybe<protocol::Runtime::ExceptionDetails>* exceptionDetails) {
   if (!isPaused()) return Response::Error(kDebuggerNotPaused);
   InjectedScript::CallFrameScope scope(m_inspector, m_session->contextGroupId(),
@@ -706,7 +706,7 @@ Response V8DebuggerAgentImpl::evaluateOnCallFrame(
 
   v8::MaybeLocal<v8::Value> maybeResultValue =
       m_pausedCallFrames[scope.frameOrdinal()]->evaluate(
-          toV8String(m_isolate, expression));
+          toV8String(m_isolate, expression), allowSideEffect.fromMaybe(true));
 
   // Re-initialize after running client's code, as it could have destroyed
   // context or session.