Relanding the language detection.

chrome/browser/cld_helper.cc

+// Copyright (c) 2009 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 "chrome/browser/cld_helper.h"
+
+#include "chrome/browser/chrome_thread.h"
+#include "chrome/browser/tab_contents/tab_contents.h"
+#include "chrome/common/notification_service.h"
+
+#if defined(OS_WIN)
+// TODO(port): The compact language detection library works only for Windows.
+#include "third_party/cld/bar/toolbar/cld/i18n/encodings/compact_lang_det/win/cld_unicodetext.h"
+#endif
+
+CLDHelper::CLDHelper(TabContents* tab_contents, int renderer_process_id,
+                     int page_id, const std::wstring& page_content)
+    : tab_contents_(tab_contents),
+      renderer_process_id_(renderer_process_id),
+      page_id_(page_id),
+      page_content_(page_content) {
+}
+
+void CLDHelper::DetectLanguage() {
+  DCHECK(ChromeThread::CurrentlyOn(ChromeThread::UI));
+
+  // Balanced in DetectionDone.
+  AddRef();
+
+  // Do the actual work on the file thread.
+  ChromeThread::PostTask(ChromeThread::FILE, FROM_HERE,
+                         NewRunnableMethod(this, &CLDHelper::DoDetectLanguage));
+}
+
+void CLDHelper::CancelLanguageDetection() {
+  tab_contents_ = NULL;
+}
+
+void CLDHelper::DoDetectLanguage() {
+  if (!tab_contents_) {
+    // If we have already been canceled, no need to perform the detection.
+    Release();  // Balance AddRef from DetectLanguage().
+    return;
+  }
+
+#if defined(OS_WIN)  // Only for windows.
+  int num_languages = 0;
+  bool is_reliable = false;
+
+  const char* language_iso_code = LanguageCodeISO639_1(
+      DetectLanguageOfUnicodeText(NULL, page_content_.c_str(), true,
+                                  &is_reliable, &num_languages, NULL));
+  language_ = language_iso_code;
+#else
+  // TODO(jcampan): port the compact language detection library.
+  NOTIMPLEMENTED();
+#endif
+
+  // Work is done, notify the RenderViewHost on the UI thread.
+  ChromeThread::PostTask(ChromeThread::UI, FROM_HERE,
+                         NewRunnableMethod(this, &CLDHelper::DetectionDone));
+}
+
+void CLDHelper::DetectionDone() {
+  if (tab_contents_)
+    tab_contents_->PageLanguageDetected();
+
+  // Remove the ref we added to ourself in DetectLanguage().
+  Release();
+}