Revert of Revert "Typecheck JS files for chrome://extensions"

extensions/browser/extension_error.cc

 // Copyright 2013 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/browser/extension_error.h"
 
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/values.h"
 #include "extensions/common/constants.h"
@@ skipping 140 matching lines @@
       stack_trace_(stack_trace),
       render_view_id_(render_view_id),
       render_process_id_(render_process_id) {
   CleanUpInit();
 }
 
 RuntimeError::~RuntimeError() {
 }
 
 scoped_ptr<DictionaryValue> RuntimeError::ToValue() const {
+  // The items which are to be written into value are also described in
+  // chrome/browser/resources/extensions/extension_error_overlay.js in @typedef
+  // for RuntimeError and StackTrace. Please update them whenever you add or
+  // remove any keys here.
   scoped_ptr<DictionaryValue> value = ExtensionError::ToValue();
   value->SetString(kContextUrlKey, context_url_.spec());
   value->SetInteger(kRenderViewIdKey, render_view_id_);
   value->SetInteger(kRenderProcessIdKey, render_process_id_);
 
   base::ListValue* trace_value = new base::ListValue;
   for (StackTrace::const_iterator iter = stack_trace_.begin();
        iter != stack_trace_.end(); ++iter) {
     DictionaryValue* frame_value = new DictionaryValue;
     frame_value->SetInteger(kLineNumberKey, iter->line_number);
@@ skipping 53 matching lines @@
   // other systems), the source won't match up with the final entry in the stack
   // trace. (For instance, in a browser action error, the source is the page -
   // sometimes the background page - but the error is thrown from the script.)
   // Make the source match the stack trace, since that is more likely the cause
   // of the error.
   if (!stack_trace_.empty() && source_ != stack_trace_[0].source)
     source_ = stack_trace_[0].source;
 }
 
 }  // namespace extensions