Allow WebStateObserver to observe N WebStates [34/N].

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

Pass the WebState to SadTabTabHelperTestDelegate to
fix the unit test (as WebStateObserver method web_state
always return nullptr).

Bug: 775684
Change-Id: I7908650e3612645eddf03eb7ea01f88dfba4d395
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/768724
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#517791}

ios/chrome/browser/ui/sad_tab/sad_tab_legacy_coordinator.mm

@@ -27,17 +27,18 @@
 #pragma mark - SadTabTabHelperDelegate
 
 - (void)sadTabTabHelper:(SadTabTabHelper*)tabHelper
-    presentSadTabForRepeatedFailure:(BOOL)repeatedFailure {
+    presentSadTabForWebState:(web::WebState*)webState
+             repeatedFailure:(BOOL)repeatedFailure {
   // Create a SadTabView so |webstate| presents it.
   SadTabView* sadTabview = [[SadTabView alloc]
            initWithMode:repeatedFailure ? SadTabViewMode::FEEDBACK
                                         : SadTabViewMode::RELOAD
-      navigationManager:tabHelper->web_state()->GetNavigationManager()];
+      navigationManager:webState->GetNavigationManager()];
   sadTabview.dispatcher = static_cast<id<ApplicationCommands>>(self.dispatcher);
   sadTabview.actionDelegate = self;
   CRWContentView* contentView =
       [[CRWGenericContentView alloc] initWithView:sadTabview];
-  tabHelper->web_state()->ShowTransientContentView(contentView);
+  webState->ShowTransientContentView(contentView);
 }
 
 @end

ios/chrome/browser/web/sad_tab_tab_helper.h

@@ -78,6 +78,10 @@ class SadTabTabHelper : public web::WebStateUserData<SadTabTabHelper>,
   // to be considered a repeat failure.
   static const double kDefaultRepeatFailureInterval;
 
+  // The WebState this instance is observing. Will be null after
+  // WebStateDestroyed has been called.
+  web::WebState* web_state_ = nullptr;
+
   // Stores the last URL that caused a renderer crash,
   // used to detect repeated crashes.
   GURL last_failed_url_;

ios/chrome/browser/web/sad_tab_tab_helper.mm

@@ -7,6 +7,7 @@
 #import <Foundation/Foundation.h>
 #import <UIKit/UIKit.h>
 
+#include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "base/strings/sys_string_conversions.h"
 #include "ios/chrome/browser/chrome_url_constants.h"
@@ -38,14 +39,16 @@ SadTabTabHelper::SadTabTabHelper(web::WebState* web_state,
 SadTabTabHelper::SadTabTabHelper(web::WebState* web_state,
                                  double repeat_failure_interval,
                                  id<SadTabTabHelperDelegate> delegate)
-    : web::WebStateObserver(web_state),
+    : web_state_(web_state),
       repeat_failure_interval_(repeat_failure_interval),
       delegate_(delegate) {
+  web_state_->AddObserver(this);
   AddApplicationDidBecomeActiveObserver();
 }
 
 SadTabTabHelper::~SadTabTabHelper() {
   DCHECK(!application_did_become_active_observer_);
+  DCHECK(!web_state_);
 }
 
 void SadTabTabHelper::CreateForWebState(web::WebState* web_state,
@@ -73,6 +76,7 @@ void SadTabTabHelper::SetDelegate(id<SadTabTabHelperDelegate> delegate) {
 }
 
 void SadTabTabHelper::WasShown(web::WebState* web_state) {
+  DCHECK_EQ(web_state_, web_state);
   if (requires_reload_on_becoming_visible_) {
     ReloadTab();
     requires_reload_on_becoming_visible_ = false;
@@ -80,6 +84,7 @@ void SadTabTabHelper::WasShown(web::WebState* web_state) {
 }
 
 void SadTabTabHelper::RenderProcessGone(web::WebState* web_state) {
+  DCHECK_EQ(web_state_, web_state);
   if (!web_state->IsVisible()) {
     requires_reload_on_becoming_visible_ = true;
     return;
@@ -99,6 +104,7 @@ void SadTabTabHelper::RenderProcessGone(web::WebState* web_state) {
 void SadTabTabHelper::DidFinishNavigation(
     web::WebState* web_state,
     web::NavigationContext* navigation_context) {
+  DCHECK_EQ(web_state_, web_state);
   if (navigation_context->GetUrl().host() == kChromeUICrashHost &&
       navigation_context->GetUrl().scheme() == kChromeUIScheme) {
     PresentSadTab(navigation_context->GetUrl());
@@ -106,6 +112,9 @@ void SadTabTabHelper::DidFinishNavigation(
 }
 
 void SadTabTabHelper::WebStateDestroyed(web::WebState* web_state) {
+  DCHECK_EQ(web_state_, web_state);
+  web_state_->RemoveObserver(this);
+  web_state_ = nullptr;
   RemoveApplicationDidBecomeActiveObserver();
 }
 
@@ -120,22 +129,23 @@ void SadTabTabHelper::PresentSadTab(const GURL& url_causing_failure) {
        seconds_since_last_failure < repeat_failure_interval_);
 
   [delegate_ sadTabTabHelper:this
-      presentSadTabForRepeatedFailure:repeated_failure];
+      presentSadTabForWebState:web_state_
+               repeatedFailure:repeated_failure];
 
   last_failed_url_ = url_causing_failure;
   last_failed_timer_ = base::MakeUnique<base::ElapsedTimer>();
 }
 
 void SadTabTabHelper::ReloadTab() {
-  PagePlaceholderTabHelper::FromWebState(web_state())
+  PagePlaceholderTabHelper::FromWebState(web_state_)
       ->AddPlaceholderForNextNavigation();
-  web_state()->GetNavigationManager()->LoadIfNecessary();
+  web_state_->GetNavigationManager()->LoadIfNecessary();
 }
 
 void SadTabTabHelper::OnAppDidBecomeActive() {
   if (!requires_reload_on_becoming_active_)
     return;
-  if (web_state()->IsVisible()) {
+  if (web_state_->IsVisible()) {
     ReloadTab();
   } else {
     requires_reload_on_becoming_visible_ = true;

ios/chrome/browser/web/sad_tab_tab_helper_delegate.h

@@ -9,12 +9,17 @@
 
 class SadTabTabHelper;
 
+namespace web {
+class WebState;
+}
+
 // Delegate for SadTabTabHelper.
 @protocol SadTabTabHelperDelegate<NSObject>
 
 // Asks the delegate to present a SadTabView.
 - (void)sadTabTabHelper:(SadTabTabHelper*)tabHelper
-    presentSadTabForRepeatedFailure:(BOOL)repeatedFailure;
+    presentSadTabForWebState:(web::WebState*)webState
+             repeatedFailure:(BOOL)repeatedFailure;
 
 @end
 

ios/chrome/browser/web/sad_tab_tab_helper_unittest.mm

@@ -33,11 +33,12 @@
 @synthesize repeatedFailure = _repeatedFailure;
 
 - (void)sadTabTabHelper:(SadTabTabHelper*)tabHelper
-    presentSadTabForRepeatedFailure:(BOOL)repeatedFailure {
+    presentSadTabForWebState:(web::WebState*)webState
+             repeatedFailure:(BOOL)repeatedFailure {
   self.repeatedFailure = repeatedFailure;
   CRWContentView* contentView = [[CRWGenericContentView alloc]
       initWithView:[[UIView alloc] initWithFrame:CGRectZero]];
-  tabHelper->web_state()->ShowTransientContentView(contentView);
+  webState->ShowTransientContentView(contentView);
 }
 
 @end