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

extensions/renderer/module_system.cc

Index: extensions/renderer/module_system.cc
diff --git a/extensions/renderer/module_system.cc b/extensions/renderer/module_system.cc
index 1e121051e767869bf0689ae4fc8c06276289edec..270e5426b10b73844f0a3d1bc0302ac36912a655 100644
--- a/extensions/renderer/module_system.cc
+++ b/extensions/renderer/module_system.cc
@@ -563,8 +563,14 @@ v8::Handle<v8::String> ModuleSystem::WrapSource(v8::Handle<v8::String> source) {
 
 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::Exception::TypeError(
+            args[0]->IsUndefined() ?

[not at google - send to devlin, 2014/12/08 22:48:11]

I think the ternary here looks pretty weird. I had to read every line of code to
figure out what happened. IMO separating out into 2 cases, the if-undefined
case, and the else-if-otherwise-invalid case, would be better. However, I don't
feel feel that strongly.

[robwu, 2014/12/08 22:51:27]

Would it help if I put the ? and : at the start of the line? I used a ternary
because I wanted to emphasize that this branch throws an error regardless of the
message.

[robwu, 2014/12/08 23:08:38]

Done (I put ? and : in front of the line and ran git cl format extensions).

+            "Method called without a valid receiver (this)."
+            "Did you forget to call .bind()?" :
+            "Invalid invocation: this is not an object!"));
+    return;
+  }
   v8::Local<v8::Object> obj = args[0].As<v8::Object>();
   v8::Local<v8::String> privates_key =
       v8::String::NewFromUtf8(GetIsolate(), "privates");