[api] deprecate v8::Function::IsBuiltin.

R=jochen@chromium.org, kozyatinskiy@chromium.org

Review-Url: https://codereview.chromium.org/2510633002
Cr-Commit-Position: refs/heads/master@{#41060}

include/v8.h

@@ -3695,7 +3695,7 @@ class V8_EXPORT Function : public Object {
   /**
    * Tells whether this function is builtin.
    */
-  bool IsBuiltin() const;
+  V8_DEPRECATED("this should no longer be used.", bool IsBuiltin() const);
 
   /**
    * Returns scriptId.

test/cctest/test-api.cc

@@ -19018,24 +19018,6 @@ THREADED_TEST(ScriptColumnNumber) {
 }
 
 
-THREADED_TEST(FunctionIsBuiltin) {
-  LocalContext env;
-  v8::Isolate* isolate = env->GetIsolate();
-  v8::HandleScope scope(isolate);
-  v8::Local<v8::Function> f;
-  f = v8::Local<v8::Function>::Cast(CompileRun("Math.floor"));
-  CHECK(f->IsBuiltin());
-  f = v8::Local<v8::Function>::Cast(CompileRun("Object"));
-  CHECK(f->IsBuiltin());
-  f = v8::Local<v8::Function>::Cast(CompileRun("Object.__defineSetter__"));
-  CHECK(f->IsBuiltin());
-  f = v8::Local<v8::Function>::Cast(CompileRun("Array.prototype.toString"));
-  CHECK(f->IsBuiltin());
-  f = v8::Local<v8::Function>::Cast(CompileRun("function a() {}; a;"));
-  CHECK(!f->IsBuiltin());
-}
-
-
 THREADED_TEST(FunctionGetScriptId) {
   LocalContext env;
   v8::Isolate* isolate = env->GetIsolate();