DevTools: issue detach notification when frontend api connection is kicked out.

chrome/browser/devtools/devtools_ui_bindings.cc

Index: chrome/browser/devtools/devtools_ui_bindings.cc
diff --git a/chrome/browser/devtools/devtools_ui_bindings.cc b/chrome/browser/devtools/devtools_ui_bindings.cc
index 1620d733b218d1cd68b0092bba0485b9ddb09cae..664627cda0ad1de2c52a65d750db6dccfc1c2bb9 100644
--- a/chrome/browser/devtools/devtools_ui_bindings.cc
+++ b/chrome/browser/devtools/devtools_ui_bindings.cc
@@ -401,6 +401,10 @@ void DevToolsUIBindings::WebSocketAPIChannel::DispatchOnClientHost(
 }
 
 void DevToolsUIBindings::WebSocketAPIChannel::ConnectionClosed() {
+  if (bindings_) {
+    bindings_->CallClientFunction("DevToolsAPI.frontendAPIDetached",
+                                  nullptr, nullptr, nullptr);
+  }
   if (attached_proxy_)
     attached_proxy_->ConnectionClosed();
 }