[inspector] fixed all shorten-64-to-32 warnings

src/inspector/V8RuntimeAgentImpl.cpp

Index: src/inspector/V8RuntimeAgentImpl.cpp
diff --git a/src/inspector/V8RuntimeAgentImpl.cpp b/src/inspector/V8RuntimeAgentImpl.cpp
index c018fba1feafefe15ab095e7709b17e87ce59e7b..1e22b3c978167011495eb76a5472186d1cb97452 100644
--- a/src/inspector/V8RuntimeAgentImpl.cpp
+++ b/src/inspector/V8RuntimeAgentImpl.cpp
@@ -364,7 +364,7 @@ void V8RuntimeAgentImpl::callFunctionOn(
   if (optionalArguments.isJust()) {
     protocol::Array<protocol::Runtime::CallArgument>* arguments =
         optionalArguments.fromJust();
-    argc = arguments->length();
+    argc = static_cast<int>(arguments->length());
     argv.reset(new v8::Local<v8::Value>[argc]);
     for (int i = 0; i < argc; ++i) {
       v8::Local<v8::Value> argumentValue;