Implement chrome.extension.connectExternal and fix various API inconsistencies.

chrome/renderer/extensions/renderer_extension_bindings.cc

Index: chrome/renderer/extensions/renderer_extension_bindings.cc
diff --git a/chrome/renderer/extensions/renderer_extension_bindings.cc b/chrome/renderer/extensions/renderer_extension_bindings.cc
index 374e6732a480eff6ed18f9e0031ce28bf30021d4..de958d1323f97892cf8debe366ae70ca39f1ae47 100644
--- a/chrome/renderer/extensions/renderer_extension_bindings.cc
+++ b/chrome/renderer/extensions/renderer_extension_bindings.cc
@@ -77,12 +77,15 @@ class ExtensionImpl : public ExtensionBase {
     if (!renderview)
       return v8::Undefined();
 
-    if (args.Length() >= 2 && args[0]->IsString() && args[1]->IsString()) {
-      std::string id = *v8::String::Utf8Value(args[0]->ToString());
-      std::string channel_name = *v8::String::Utf8Value(args[1]->ToString());
+    if (args.Length() >= 3 && args[0]->IsString() && args[1]->IsString() &&
+        args[2]->IsString()) {
+      std::string source_id = *v8::String::Utf8Value(args[0]->ToString());
+      std::string target_id = *v8::String::Utf8Value(args[1]->ToString());
+      std::string channel_name = *v8::String::Utf8Value(args[2]->ToString());
       int port_id = -1;
       renderview->Send(new ViewHostMsg_OpenChannelToExtension(
-          renderview->routing_id(), id, channel_name, &port_id));
+          renderview->routing_id(), source_id, target_id,
+          channel_name, &port_id));
       return v8::Integer::New(port_id);
     }
     return v8::Undefined();