Implement externally_connectable! Web pages can now communicate directly with

chrome/renderer/extensions/runtime_custom_bindings.cc

Index: chrome/renderer/extensions/runtime_custom_bindings.cc
diff --git a/chrome/renderer/extensions/runtime_custom_bindings.cc b/chrome/renderer/extensions/runtime_custom_bindings.cc
index 0f4801fbc6ad3b93bb46297e8c3e7ca2bc92f2c4..a0496d0a38deb21a61ba78d24b0b7640731f151b 100644
--- a/chrome/renderer/extensions/runtime_custom_bindings.cc
+++ b/chrome/renderer/extensions/runtime_custom_bindings.cc
@@ -47,16 +47,14 @@ v8::Handle<v8::Value> RuntimeCustomBindings::OpenChannelToExtension(
     return v8::Undefined();
 
   // The Javascript code should validate/fill the arguments.
-  CHECK(args.Length() >= 3 &&
-        args[0]->IsString() &&
-        args[1]->IsString() &&
-        args[2]->IsString());
+  CHECK_EQ(2, args.Length());
+  CHECK(args[0]->IsString() && args[1]->IsString());
 
   ExtensionMsg_ExternalConnectionInfo info;

[Jeffrey Yasskin, 2013/06/08 00:28:09]

This is where you'd need to record whether the event was user-initiated, right?
https://code.google.com/p/chromium/issues/detail?id=55316#c66

[not at google - send to devlin, 2013/06/08 02:02:33]

Yeah, but it's something for developers not something we're gating this API call
on. I'll do in a follow up.

-  info.source_id = *v8::String::Utf8Value(args[0]->ToString());
-  info.target_id = *v8::String::Utf8Value(args[1]->ToString());
+  info.source_id = context()->extension() ? context()->extension()->id() : "";
+  info.target_id = *v8::String::Utf8Value(args[0]->ToString());
   info.source_url = renderview->GetWebView()->mainFrame()->document().url();
-  std::string channel_name = *v8::String::Utf8Value(args[2]->ToString());
+  std::string channel_name = *v8::String::Utf8Value(args[1]->ToString());
   int port_id = -1;
   renderview->Send(new ExtensionHostMsg_OpenChannelToExtension(
       renderview->GetRoutingID(), info, channel_name, &port_id));