Implements the auto-translate on click: if you have translated

a page and are navigating to a new page in the same language by
clicking a link, the new page is automatically translated.
In order to do that I moved the language state from the navigation
entry to some dedicated class that each TabContents owns.
Also added some basic unit-testing for good measure.

BUG=35477
TEST=See bug steps. Run unit-tests.
 
Review URL: http://codereview.chromium.org/596092

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@38961 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 51 insertions, 0 deletions

diff --git a/chrome/browser/tab_contents/language_state.cc b/chrome/browser/tab_contents/language_state.cc
new file mode 100644
index 0000000..8522ed3
--- /dev/null
+++ b/chrome/browser/tab_contents/language_state.cc
@@ -0,0 +1,51 @@
+// Copyright (c) 2010 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/tab_contents/language_state.h"
+
+#include "chrome/browser/tab_contents/navigation_controller.h"
+#include "chrome/browser/tab_contents/navigation_entry.h"
+
+LanguageState::LanguageState(NavigationController* nav_controller)
+    : navigation_controller_(nav_controller),
+      translation_pending_(false) {
+}
+
+LanguageState::~LanguageState() {
+}
+
+void LanguageState::DidNavigate() {
+  prev_original_lang_ = original_lang_;
+  prev_current_lang_ = current_lang_;
+
+  original_lang_.clear();
+  current_lang_.clear();
+
+  translation_pending_ = false;
+}
+
+void LanguageState::LanguageDetermined(const std::string& page_language) {
+  original_lang_ = page_language;
+  current_lang_ = page_language;
+}
+
+std::string LanguageState::AutoTranslateTo() const {
+  // Only auto-translate if:
+  // - no translation is pending
+  // - this page is in the same language as the previous page
+  // - the previous page had been translated
+  // - this page is not already translated
+  // - the new page was navigated through a link.
+  if (!translation_pending_ &&
+      prev_original_lang_ == original_lang_ &&
+      prev_original_lang_ != prev_current_lang_ &&
+      original_lang_ == current_lang_ &&
+      navigation_controller_->GetActiveEntry() &&
+      navigation_controller_->GetActiveEntry()->transition_type() ==
+          PageTransition::LINK) {
+    return prev_current_lang_;
+  }
+
+  return std::string();
+}