[Translate] Migrate IPCs to Mojo interfaces.

components/translate/content/public/interfaces/translate.mojom

+// 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.
+
+module translate.mojom;
+
+import "mojo/common/common_custom_types.mojom";
+import "url/mojo/url.mojom";
+
+// enum translate::TranslateErrors::Type

[Ken Rockot(use gerrit already), 2016/07/28 20:16:06]

I don't think we should reference typemapped types in the mojom file. We
intentionally keep typemaps separate from mojom because an arbitrary typemap may
be applied to this type in any given build config.

[leonhsl(Using Gerrit), 2016/07/29 12:54:32]

Yeah, it is true. Done. Also removed other similar comments.

+enum TranslateErrorsType {

[Ken Rockot(use gerrit already), 2016/07/28 20:16:06]

nit: TranslateError seems like a better name?

[leonhsl(Using Gerrit), 2016/07/29 12:54:32]

Done.

+  NONE,
+  NETWORK,
+  INITIALIZATION_ERROR,
+  UNKNOWN_LANGUAGE,
+  UNSUPPORTED_LANGUAGE,
+  IDENTICAL_LANGUAGES,
+  TRANSLATION_ERROR,
+  TRANSLATION_TIMEOUT,
+  UNEXPECTED_SCRIPT_ERROR,
+  BAD_ORIGIN,
+  SCRIPT_LOAD_ERROR,
+  TRANSLATE_ERROR_MAX,
+};
+
+// struct translate::LanguageDetectionDetails
+struct LanguageDetectionDetails {
+  mojo.common.mojom.Time time;
+  url.mojom.Url url;
+  string content_language;
+  string cld_language;
+  bool is_cld_reliable;
+  bool has_notranslate;
+  string html_root_language;
+  string adopted_language;
+  string contents;
+};
+
+interface Page {
+  // Tells the renderer to translate the page contents from one language to

[Ken Rockot(use gerrit already), 2016/07/28 20:16:06]

I wonder if we could make this documentation more clear. It also doesn't need to
refer to details like "renderer" since this could be implemented by anyone.
Something like:

// Requests that the page be translated from |source_lang| to
// |target_lang|.
//
// If a Translate request is already in progress with a matching
// |target_lang|, this request will respond with |cancelled| set
// to |true|.
//
// If a Translate request is already in progress with a different
// |target_lang|, that request will respond with |cancelled| set
// to |true| and this request will proceed normally.
//
// If |cancelled| is |true| all other response values should be
// ignored.

[leonhsl(Using Gerrit), 2016/07/29 12:54:32]

Aha,, Thank you!! Now it's very clear and easy to understand!

+  // another.
+  // When overlapping calls happened, for example,
+  // #2 call comes up while #1 call is still running:
+  // IF #2 target_lang is the same with #1,
+  //   #2 will do nothing but just returns |cancelled| parameter as true;
+  // ELSE
+  //   #1 will be cancelled and returns |cancelled| parameter as true.
+  // In case of true |cancelled|, callers should ignore other parameters.
+  Translate(string translate_script, string source_lang, string target_lang)
+      => (bool cancelled,
+          string original_lang,
+          string translated_lang,
+          TranslateErrorsType error_type);
+
+  // Tells the renderer to revert the text of translated page to its original
+  // contents.
+  RevertTranslation();

[Ken Rockot(use gerrit already), 2016/07/28 20:16:06]

suggestion:

// Requests that the page be reverted to its original language with
// no translation applied.

[leonhsl(Using Gerrit), 2016/07/29 12:54:32]

Done.

+};
+
+interface ContentTranslateDriver {
+  // Notification that a new page is ready to translate,
+  // and the language for it has been determined.
+  NewPage(Page page,

[Ken Rockot(use gerrit already), 2016/07/28 20:16:06]

nit: RegisterPage? Method names should generally be imperative verb phrases.

[leonhsl(Using Gerrit), 2016/07/29 12:54:32]

Got it and done.

+          LanguageDetectionDetails details,
+          bool page_needs_translation);
+};