Allow WebStateObserver to observe N WebStates [11/N].

Convert IOSTranslateDriver to directly track registration with
the observed WebState instead of relying on the deprecated
code in WebStateObserver.

Bug: 775684
Change-Id: Iad1d53fcab9448e088a19cd75767235f9816a0b3
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Reviewed-on: https://chromium-review.googlesource.com/757105
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#515956}

components/translate/ios/browser/ios_translate_driver.h

@@ -53,6 +53,7 @@ class IOSTranslateDriver : public TranslateDriver,
   void NavigationItemCommitted(
       web::WebState* web_state,
       const web::LoadCommittedDetails& load_details) override;
+  void WebStateDestroyed(web::WebState* web_state) override;
 
   // TranslateDriver methods.
   void OnIsPageTranslatedChanged() override;
@@ -100,6 +101,10 @@ class IOSTranslateDriver : public TranslateDriver,
                            const std::string& original_language,
                            double translation_time) override;
 
+  // The WebState this instance is observing. Will be null after
+  // WebStateDestroyed has been called.
+  web::WebState* web_state_ = nullptr;
+
   // The navigation manager of the tab we are associated with.
   web::NavigationManager* navigation_manager_;
 

components/translate/ios/browser/ios_translate_driver.mm

@@ -51,7 +51,7 @@ IOSTranslateDriver::IOSTranslateDriver(
     web::WebState* web_state,
     web::NavigationManager* navigation_manager,
     TranslateManager* translate_manager)
-    : web::WebStateObserver(web_state),
+    : web_state_(web_state),
       navigation_manager_(navigation_manager),
       translate_manager_(translate_manager->GetWeakPtr()),
       page_seq_no_(0),
@@ -59,7 +59,9 @@ IOSTranslateDriver::IOSTranslateDriver(
       weak_method_factory_(this) {
   DCHECK(navigation_manager_);
   DCHECK(translate_manager_);
-  DCHECK(web::WebStateObserver::web_state());
+  DCHECK(web_state_);
+
+  web_state_->AddObserver(this);
 
   CRWJSInjectionReceiver* receiver = web_state->GetJSInjectionReceiver();
   DCHECK(receiver);
@@ -81,6 +83,10 @@ IOSTranslateDriver::IOSTranslateDriver(
 }
 
 IOSTranslateDriver::~IOSTranslateDriver() {
+  if (web_state_) {
+    web_state_->RemoveObserver(this);
+    web_state_ = nullptr;
+  }
 }
 
 language::IOSLanguageDetectionTabHelper::Callback
@@ -98,7 +104,7 @@ void IOSTranslateDriver::OnLanguageDetermined(
 
   translate_manager_->translate_client()->RecordLanguageDetectionEvent(details);
 
-  if (web_state())
+  if (web_state_)
     translate_manager_->InitiateTranslation(details.adopted_language);
 }
 
@@ -107,6 +113,8 @@ void IOSTranslateDriver::OnLanguageDetermined(
 void IOSTranslateDriver::NavigationItemCommitted(
     web::WebState* web_state,
     const web::LoadCommittedDetails& load_details) {
+  DCHECK_EQ(web_state_, web_state);
+
   // Interrupt pending translations and reset various data when a navigation
   // happens. Desktop does it by tracking changes in the page ID, and
   // through WebContentObserver, but these concepts do not exist on iOS.
@@ -122,6 +130,12 @@ void IOSTranslateDriver::NavigationItemCommitted(
                                                      true, reload);
 }
 
+void IOSTranslateDriver::WebStateDestroyed(web::WebState* web_state) {
+  DCHECK_EQ(web_state_, web_state);
+  web_state_->RemoveObserver(this);
+  web_state_ = nullptr;
+}
+
 // TranslateDriver methods
 
 bool IOSTranslateDriver::IsLinkNavigation() {
@@ -160,15 +174,15 @@ bool IOSTranslateDriver::IsIncognito() {
 }
 
 const std::string& IOSTranslateDriver::GetContentsMimeType() {
-  return web_state()->GetContentsMimeType();
+  return web_state_->GetContentsMimeType();
 }
 
 const GURL& IOSTranslateDriver::GetLastCommittedURL() {
-  return web_state()->GetLastCommittedURL();
+  return web_state_->GetLastCommittedURL();
 }
 
 const GURL& IOSTranslateDriver::GetVisibleURL() {
-  return web_state()->GetVisibleURL();
+  return web_state_->GetVisibleURL();
 }
 
 bool IOSTranslateDriver::HasCurrentPage() {
@@ -179,7 +193,7 @@ void IOSTranslateDriver::OpenUrlInNewTab(const GURL& url) {
   web::WebState::OpenURLParams params(url, web::Referrer(),
                                       WindowOpenDisposition::NEW_FOREGROUND_TAB,
                                       ui::PAGE_TRANSITION_LINK, false);
-  web_state()->OpenURL(params);
+  web_state_->OpenURL(params);
 }
 
 void IOSTranslateDriver::TranslationDidSucceed(
@@ -222,7 +236,7 @@ void IOSTranslateDriver::CheckTranslateStatus(
 
 bool IOSTranslateDriver::IsPageValid(int page_seq_no) const {
   bool user_navigated_away = page_seq_no != page_seq_no_;
-  return !user_navigated_away && web_state();
+  return !user_navigated_away && web_state_;
 }
 
 // TranslateController::Observer implementation.