Remove getRawTag and objectToString.

.internal/baseGetTag.js

@@ -1,12 +1,7 @@
-import getRawTag from './getRawTag.js'
-import objectToString from './objectToString.js'
-
-/** `Object#toString` result references. */
-const nullTag = '[object Null]'
-const undefinedTag = '[object Undefined]'
-
-/** Built-in value references. */
-const symToStringTag = Symbol ? Symbol.toStringTag : undefined
+const objectProto = Object.prototype
+const hasOwnProperty = objectProto.hasOwnProperty
+const toString = objectProto.toString
+const symToStringTag = typeof Symbol != 'undefined' ? Symbol.toStringTag : undefined
 
 /**
  * The base implementation of `getTag` without fallbacks for buggy environments.
@@ -17,11 +12,28 @@ const symToStringTag = Symbol ? Symbol.toStringTag : undefined
  */
 function baseGetTag(value) {
   if (value == null) {
-    return value === undefined ? undefinedTag : nullTag
+    return value === undefined ? '[object Undefined]' : '[object Null]'
   }
-  return (symToStringTag && symToStringTag in Object(value))
-    ? getRawTag(value)
-    : objectToString(value)
+  if (!(symToStringTag && symToStringTag in Object(value))) {
+    return toString.call(value)
+  }
+  const isOwn = hasOwnProperty.call(value, symToStringTag)
+  const tag = value[symToStringTag]
+  let unmasked = false
+  try {
+    value[symToStringTag] = undefined
+    unmasked = true
+  } catch (e) {}
+
+  const result = toString.call(value)
+  if (unmasked) {
+    if (isOwn) {
+      value[symToStringTag] = tag
+    } else {
+      delete value[symToStringTag]
+    }
+  }
+  return result
 }
 
 export default baseGetTag