Save page language in navigation entry.

Add the page language as user data on the last committed navigation entry.
Then, make SyncSessionsRouterTabHelper listen to OnLanguageDetermined.
That way, it knows when to notify that the tab's sync data has been modified.

Bug: 957657
Change-Id: Iacde546d789d325d6700be4acaaa15dc5eef7076
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1504131
Commit-Queue: Alexandre Frechette <frechette@chromium.org>
Reviewed-by: anthonyvd <anthonyvd@chromium.org>
Reviewed-by: Mikel Astiz <mastiz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#656402}

chrome/browser/sync/sessions/sync_sessions_router_tab_helper.cc

@@ -31,7 +31,13 @@ SyncSessionsRouterTabHelper::SyncSessionsRouterTabHelper(
     SyncSessionsWebContentsRouter* router)
     : content::WebContentsObserver(web_contents),
       router_(router),
-      source_tab_id_(SessionID::InvalidValue()) {}
+      source_tab_id_(SessionID::InvalidValue()) {
+  chrome_translate_client_ =
+      ChromeTranslateClient::FromWebContents(web_contents);
+  // A translate client is not always attached to web contents (e.g. tests).
+  if (chrome_translate_client_)
+    chrome_translate_client_->translate_driver().AddObserver(this);
+}
 
 SyncSessionsRouterTabHelper::~SyncSessionsRouterTabHelper() {}
 
@@ -47,6 +53,8 @@ void SyncSessionsRouterTabHelper::TitleWasSet(content::NavigationEntry* entry) {
 
 void SyncSessionsRouterTabHelper::WebContentsDestroyed() {
   NotifyRouter();
+  if (chrome_translate_client_)
+    chrome_translate_client_->translate_driver().RemoveObserver(this);
 }
 
 void SyncSessionsRouterTabHelper::DidFinishLoad(
@@ -70,6 +78,12 @@ void SyncSessionsRouterTabHelper::DidOpenRequestedURL(
   SetSourceTabIdForChild(new_contents);
 }
 
+void SyncSessionsRouterTabHelper::OnLanguageDetermined(
+    const translate::LanguageDetectionDetails& details) {
+  // TODO (crbug.com/957657): NotifyRouter() when language is synced on
+  // notification.
+}
+
 void SyncSessionsRouterTabHelper::SetSourceTabIdForChild(
     content::WebContents* child_contents) {
   SessionID source_tab_id = SessionTabHelper::IdForTab(web_contents());

chrome/browser/sync/sessions/sync_sessions_router_tab_helper.h

@@ -5,7 +5,9 @@
 #ifndef CHROME_BROWSER_SYNC_SESSIONS_SYNC_SESSIONS_ROUTER_TAB_HELPER_H_
 #define CHROME_BROWSER_SYNC_SESSIONS_SYNC_SESSIONS_ROUTER_TAB_HELPER_H_
 
+#include "chrome/browser/translate/chrome_translate_client.h"
 #include "components/sessions/core/session_id.h"
+#include "components/translate/content/browser/content_translate_driver.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "content/public/browser/web_contents_user_data.h"
 
@@ -22,7 +24,8 @@ class SyncSessionsWebContentsRouter;
 // https://chromium.googlesource.com/chromium/src/+/master/docs/tab_helpers.md
 class SyncSessionsRouterTabHelper
     : public content::WebContentsUserData<SyncSessionsRouterTabHelper>,
-      public content::WebContentsObserver {
+      public content::WebContentsObserver,
+      public translate::ContentTranslateDriver::Observer {
  public:
   ~SyncSessionsRouterTabHelper() override;
 
@@ -46,6 +49,10 @@ class SyncSessionsRouterTabHelper
                            bool started_from_context_menu,
                            bool renderer_initiated) override;
 
+  // ContentTranslateDriver::Observer implementation.
+  void OnLanguageDetermined(
+      const translate::LanguageDetectionDetails& details) override;
+
   // Sets the source tab id for the given child WebContents to the id of the
   // WebContents that owns this helper.
   void SetSourceTabIdForChild(content::WebContents* child_contents);
@@ -76,6 +83,8 @@ class SyncSessionsRouterTabHelper
   // * Click on a link with target='_blank'.
   SessionID source_tab_id_;
 
+  ChromeTranslateClient* chrome_translate_client_;
+
   WEB_CONTENTS_USER_DATA_KEY_DECL();
 
   DISALLOW_COPY_AND_ASSIGN(SyncSessionsRouterTabHelper);

components/translate/content/browser/content_translate_driver.cc

@@ -4,6 +4,7 @@
 
 #include "components/translate/content/browser/content_translate_driver.h"
 
+#include <memory>
 #include <string>
 #include <utility>
 
@@ -11,6 +12,8 @@
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/single_thread_task_runner.h"
+#include "base/strings/utf_string_conversions.h"
+#include "base/supports_user_data.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "components/google/core/common/google_util.h"
 #include "components/language/core/browser/url_language_histogram.h"
@@ -41,6 +44,15 @@ namespace {
 // loading before giving up the translation
 const int kMaxTranslateLoadCheckAttempts = 20;
 
+// The key used to store page language in the NavigationEntry;
+const char kPageLanguageKey[] = "page_language";
+
+struct LanguageDectionData : public base::SupportsUserData::Data {
+  // The adopted language. An ISO 639 language code (two letters, except for
+  // Chinese where a localization is necessary).
+  std::string adopted_language;
+};
+
 }  // namespace
 
 ContentTranslateDriver::ContentTranslateDriver(
@@ -294,9 +306,18 @@ void ContentTranslateDriver::RegisterPage(
   translate_manager_->GetLanguageState().LanguageDetermined(
       details.adopted_language, page_needs_translation);
 
-  if (web_contents())
+  if (web_contents()) {
     translate_manager_->InitiateTranslation(details.adopted_language);
 
+    // Save the page language on the navigation entry so it can be synced.
+    auto* const entry = web_contents()->GetController().GetLastCommittedEntry();
+    if (entry != nullptr) {
+      auto data = std::make_unique<LanguageDectionData>();
+      data->adopted_language = details.adopted_language;
+      entry->SetUserData(kPageLanguageKey, std::move(data));
+    }
+  }
+
   for (auto& observer : observer_list_)
     observer.OnLanguageDetermined(details);
 }