Adds extension events for custom dictionary load/change.

chrome/browser/chromeos/extensions/dictionary_event_router.cc

Index: chrome/browser/chromeos/extensions/dictionary_event_router.cc
diff --git a/chrome/browser/chromeos/extensions/dictionary_event_router.cc b/chrome/browser/chromeos/extensions/dictionary_event_router.cc
new file mode 100644
index 0000000000000000000000000000000000000000..f2c6a9d08f401dee45da12499c84d99920949aac
--- /dev/null
+++ b/chrome/browser/chromeos/extensions/dictionary_event_router.cc
@@ -0,0 +1,76 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.

[please use gerrit instead, 2015/03/05 21:43:33]

2015

[Peter Wen, 2015/03/06 16:09:09]

Done.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/chromeos/extensions/dictionary_event_router.h"
+
+#include "base/json/json_writer.h"
+#include "base/values.h"
+#include "chrome/browser/chromeos/extensions/input_method_api.h"
+#include "chrome/browser/spellchecker/spellcheck_factory.h"
+#include "chrome/browser/spellchecker/spellcheck_service.h"
+#include "content/public/browser/browser_context.h"
+#include "extensions/browser/event_router.h"
+#include "extensions/browser/extension_system.h"
+
+namespace chromeos {
+
+ExtensionDictionaryEventRouter::ExtensionDictionaryEventRouter(
+    content::BrowserContext* context)
+    : context_(context),
+      dictionary_(nullptr) {
+  SpellcheckService* spellcheck = SpellcheckServiceFactory::GetForContext(
+      context);
+  if (spellcheck) {
+    dictionary_ = spellcheck->GetCustomDictionary();
+    dictionary_->AddObserver(this);
+  }
+}
+
+ExtensionDictionaryEventRouter::~ExtensionDictionaryEventRouter() {
+  if (dictionary_) {

[please use gerrit instead, 2015/03/05 21:42:51]

No need to save "dictionary_". SpellcheckService can be null on shutdown and it
owns SpellcheckCustomDictionary, so that can be null on shutdown as well.
However "dictionary_" is never set to null. Do this in the destructor instead:

SpellcheckService* spellcheck =
SpellcheckServiceFactory::GetForContext(context_);
if (spellcheck)
  spellcheck->GetCustomDictionary()->RemoveObserver(this);

Alternatively, if you feel super productive, you can make either
SpellcheckService or SpellcheckCustomDictionary implement base::WeakPtr
interface. Then you can save either "spellcheck_" or "dictionary_" and use them
any time you want. (A base::WeakPtr will become NULL when the object is
deleted.)

[Peter Wen, 2015/03/06 16:09:09]

I changed it to use base::WeakPtr for SpellcheckService. Do you have an example
where a class can implement WeakPtr? :)

[please use gerrit instead, 2015/03/06 17:54:34]

Sorry I meant SupportsWeakPtr, like this for example:

https://code.google.com/p/chromium/codesearch#chromium/src/chrome/browser/ui/...

Your approach is also OK and is actually preferred.

+    dictionary_->RemoveObserver(this);
+  }
+}
+
+void ExtensionDictionaryEventRouter::OnCustomDictionaryLoaded() {
+  extensions::EventRouter* router = extensions::EventRouter::Get(context_);
+
+  if (!router->HasEventListener(
+      extensions::InputMethodAPI::kOnDictionaryLoaded)) {
+    return;
+  }
+
+  scoped_ptr<base::ListValue> args(new base::ListValue());
+  // The router will only send the event to extensions that are listening.
+  scoped_ptr<extensions::Event> event(new extensions::Event(
+      extensions::InputMethodAPI::kOnDictionaryLoaded, args.Pass()));
+  event->restrict_to_browser_context = context_;
+  router->BroadcastEvent(event.Pass());
+}
+
+void ExtensionDictionaryEventRouter::OnCustomDictionaryChanged(
+    const SpellcheckCustomDictionary::Change& dictionary_change) {
+  extensions::EventRouter* router = extensions::EventRouter::Get(context_);
+
+  if (!router->HasEventListener(
+      extensions::InputMethodAPI::kOnDictionaryChanged)) {
+    return;
+  }
+
+  scoped_ptr<base::ListValue> args(new base::ListValue());
+  scoped_ptr<base::ListValue> added_words(new base::ListValue());
+  scoped_ptr<base::ListValue> removed_words(new base::ListValue());
+  added_words->AppendStrings(dictionary_change.to_add());
+  removed_words->AppendStrings(dictionary_change.to_remove());
+  args->Append(added_words.release());
+  args->Append(removed_words.release());
+
+  // The router will only send the event to extensions that are listening.
+  scoped_ptr<extensions::Event> event(new extensions::Event(
+      extensions::InputMethodAPI::kOnDictionaryChanged, args.Pass()));
+  event->restrict_to_browser_context = context_;
+  router->BroadcastEvent(event.Pass());
+}
+
+}  // namespace chromeos