Send port disconnect events when a frame is unloaded.

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 f7197974ee995c7e8ee224c0ffeac546f46ed45e..4cff1dd86338d3549cfeb7fc6490fd5fbceba7e0 100644
--- a/chrome/renderer/extensions/renderer_extension_bindings.cc
+++ b/chrome/renderer/extensions/renderer_extension_bindings.cc
@@ -46,6 +46,8 @@ class ExtensionImpl : public ExtensionBase {
       return v8::FunctionTemplate::New(OpenChannelToExtension);
     } else if (name->Equals(v8::String::New("PostMessage"))) {
       return v8::FunctionTemplate::New(PostMessage);
+    } else if (name->Equals(v8::String::New("CloseChannel"))) {
+      return v8::FunctionTemplate::New(CloseChannel);
     }
     return ExtensionBase::GetNativeFunction(name);
   }
@@ -83,6 +85,17 @@ class ExtensionImpl : public ExtensionBase {
     }
     return v8::Undefined();
   }
+
+  // Sends a message along the given channel.
+  static v8::Handle<v8::Value> CloseChannel(const v8::Arguments& args) {
+    if (args.Length() >= 1 && args[0]->IsInt32()) {
+      int port_id = args[0]->Int32Value();
+      // Send via the RenderThread because the RenderView might be closing.
+      EventBindings::GetRenderThread()->Send(
+          new ViewHostMsg_ExtensionCloseChannel(port_id));
+    }
+    return v8::Undefined();
+  }
 };
 
 // Convert a ListValue to a vector of V8 values.