Allow WebStateObserver to observe N WebStates [19/N].

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

Remove unused method InfoBarManagerImpl::WebStateFromInfoBar
as it accessed deprecated web_state() method.

Bug: 775684
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: I55574e425107a3306bc0ba2085d699d4008c3f44
Reviewed-on: https://chromium-review.googlesource.com/766750
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#516296}

ios/chrome/browser/infobars/infobar_manager_impl.h

@@ -29,11 +29,6 @@ class InfoBarManagerImpl : public infobars::InfoBarManager,
  public:
   ~InfoBarManagerImpl() override;
 
-  // This function must only be called on infobars that are owned by an
-  // InfoBarManagerImpl instance (or not owned at all, in which case this
-  // returns null).
-  static web::WebState* WebStateFromInfoBar(infobars::InfoBar* infobar);
-
  private:
   friend class web::WebStateUserData<InfoBarManagerImpl>;
 
@@ -53,6 +48,10 @@ class InfoBarManagerImpl : public infobars::InfoBarManager,
   // Opens a URL according to the specified |disposition|.
   void OpenURL(const GURL& url, WindowOpenDisposition disposition) override;
 
+  // The WebState this instance is observing. Will be null after
+  // WebStateDestroyed has been called.
+  web::WebState* web_state_ = nullptr;
+
   DISALLOW_COPY_AND_ASSIGN(InfoBarManagerImpl);
 };
 

ios/chrome/browser/infobars/infobar_manager_impl.mm

@@ -6,6 +6,7 @@
 
 #include <utility>
 
+#include "base/logging.h"
 #include "components/infobars/core/confirm_infobar_delegate.h"
 #include "components/infobars/core/infobar.h"
 #include "components/infobars/core/infobar_delegate.h"
@@ -43,26 +44,26 @@ NavigationDetailsFromLoadCommittedDetails(
 
 }  // namespace
 
-// static
-web::WebState* InfoBarManagerImpl::WebStateFromInfoBar(
-    infobars::InfoBar* infobar) {
-  if (!infobar || !infobar->owner())
-    return nullptr;
-  return static_cast<InfoBarManagerImpl*>(infobar->owner())->web_state();
-}
-
 InfoBarManagerImpl::InfoBarManagerImpl(web::WebState* web_state)
-    : web::WebStateObserver(web_state) {
-  DCHECK(web_state);
+    : web_state_(web_state) {
+  web_state_->AddObserver(this);
 }
 
 InfoBarManagerImpl::~InfoBarManagerImpl() {
   ShutDown();
+
+  // As the object can commit suicide, it is possible that its destructor
+  // is called before WebStateDestroyed. In that case stop observing the
+  // WebState.
+  if (web_state_) {
+    web_state_->RemoveObserver(this);
+    web_state_ = nullptr;
+  }
 }
 
 int InfoBarManagerImpl::GetActiveEntryID() {
   web::NavigationItem* visible_item =
-      web_state()->GetNavigationManager()->GetVisibleItem();
+      web_state_->GetNavigationManager()->GetVisibleItem();
   return visible_item ? visible_item->GetUniqueID() : 0;
 }
 
@@ -74,16 +75,17 @@ std::unique_ptr<infobars::InfoBar> InfoBarManagerImpl::CreateConfirmInfoBar(
 void InfoBarManagerImpl::NavigationItemCommitted(
     web::WebState* web_state,
     const web::LoadCommittedDetails& load_details) {
+  DCHECK_EQ(web_state_, web_state);
   OnNavigation(NavigationDetailsFromLoadCommittedDetails(load_details));
 }
 
 void InfoBarManagerImpl::WebStateDestroyed(web::WebState* web_state) {
+  DCHECK_EQ(web_state_, web_state);
   // The WebState is going away; be aggressively paranoid and delete this
   // InfoBarManagerImpl lest other parts of the system attempt to add infobars
-  // or use it otherwise during the destruction.
-  web_state->RemoveUserData(UserDataKey());
-  // That was the equivalent of "delete this". This object is now destroyed;
-  // returning from this function is the only safe thing to do.
+  // or use it otherwise during the destruction. As this is the equivalent of
+  // "delete this", returning from this function is the only safe thing to do.
+  web_state_->RemoveUserData(UserDataKey());
 }
 
 void InfoBarManagerImpl::OpenURL(const GURL& url,