[Extension Bindings] Test event listeners throwing exceptions

extensions/renderer/event_emitter.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "extensions/renderer/event_emitter.h"
 
 #include <algorithm>
 
 #include "gin/object_template_builder.h"
 #include "gin/per_context_data.h"
@@ skipping 23 matching lines @@
 
 void EventEmitter::Fire(v8::Local<v8::Context> context,
                         std::vector<v8::Local<v8::Value>>* args) {
   // We create a local copy of listeners_ since the array can be modified during
   // handling.
   std::vector<v8::Local<v8::Function>> listeners;
   listeners.reserve(listeners_.size());
   for (const auto& listener : listeners_)
     listeners.push_back(listener.Get(context->GetIsolate()));
 
-  for (const auto& listener : listeners)
+  for (const auto& listener : listeners) {
+    v8::TryCatch try_catch(context->GetIsolate());
+    // SetVerbose() means the error will still get logged, which is what we
+    // want. We don't let it bubble up any further to prevent it from being
+    // surfaced in e.g. JS code that triggered the event.
+    try_catch.SetVerbose(true);
     run_js_.Run(listener, context, args->size(), args->data());
+  }
 }
 
 void EventEmitter::AddListener(gin::Arguments* arguments) {
   v8::Local<v8::Function> listener;
   if (!arguments->GetNext(&listener))
     return;
 
   v8::Local<v8::Object> holder;
   CHECK(arguments->GetHolder(&holder));
   CHECK(!holder.IsEmpty());
@@ skipping 29 matching lines @@
       arguments->isolate()->GetCurrentContext();
   std::vector<v8::Local<v8::Value>> v8_args;
   if (arguments->Length() > 0) {
     // Converting to v8::Values should never fail.
     CHECK(arguments->GetRemaining(&v8_args));
   }
   Fire(context, &v8_args);
 }
 
 }  // namespace extensions