Throw JavaScript error instead of CHECK when this in privates is invalid

extensions/renderer/module_system.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "extensions/renderer/module_system.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
 #include "base/stl_util.h"
@@ skipping 545 matching lines @@
       "console, privates,"
       "$Array, $Function, $JSON, $Object, $RegExp, $String, $Error) {"
       "'use strict';");
   v8::Handle<v8::String> right = v8::String::NewFromUtf8(GetIsolate(), "\n})");
   return handle_scope.Escape(v8::Local<v8::String>(
       v8::String::Concat(left, v8::String::Concat(source, right))));
 }
 
 void ModuleSystem::Private(const v8::FunctionCallbackInfo<v8::Value>& args) {
   CHECK_EQ(1, args.Length());
-  CHECK(args[0]->IsObject());
-  CHECK(!args[0]->IsNull());
+  if (!args[0]->IsObject() || args[0]->IsNull()) {
+    GetIsolate()->ThrowException(
+        v8::String::NewFromUtf8(GetIsolate(),
+                                "Invalid invocation: this is not an object!"));
+    return;

[not at google - send to devlin, 2014/12/08 22:29:11]

Good catch, I think this is the right behaviour, though
- should throw a TypeError
- the explanation could be better and differentiate between wrong type and
undefined type. The former is something dumb, the latter is something subtle
that every JS programmer makes at some point.

So I'd say like:

if (args[0]->IsUndefined()) {
  GetIsolate()->ThrowException(v8::Exception::TypeError(
      "Method called without a receiver. Did you forget to call .bind()?");
}
... etc.

[robwu, 2014/12/08 22:39:24]

Done.

+  }
   v8::Local<v8::Object> obj = args[0].As<v8::Object>();
   v8::Local<v8::String> privates_key =
       v8::String::NewFromUtf8(GetIsolate(), "privates");
   v8::Local<v8::Value> privates = obj->GetHiddenValue(privates_key);
   if (privates.IsEmpty()) {
     privates = v8::Object::New(args.GetIsolate());
     if (privates.IsEmpty()) {
       GetIsolate()->ThrowException(
           v8::String::NewFromUtf8(GetIsolate(), "Failed to create privates"));
       return;
@@ skipping 92 matching lines @@
     v8::Handle<v8::Value> value) {
   if (!is_valid())
     return;
   v8::HandleScope handle_scope(GetIsolate());
   v8::Handle<v8::Promise::Resolver> resolver_local(
       v8::Local<v8::Promise::Resolver>::New(GetIsolate(), *resolver));
   resolver_local->Resolve(value);
 }
 
 }  // namespace extensions