[ios] Fix kRestoreNavigationTime histogram.

kRestoreNavigationTime was a timer created by WKBasedNavigationManagerImpl::Restore
and stopped when session restoration begins navigating to its final URL.

Unfortunately, WKBasedNavigationManagerImpl::Restore is called for every restored
WebState on startup.  Actual network access doesn't happen until a tab is selected. That
means if you have 10 tabs, background/kill/restore, navigate a bit, and then change tabs,
that second tab will have had a timer running since the app started.

Instead, start kRestoreNavigationTime when ios/web begins loading the restore page, and
finish the timer when ios/web begins loading the real page.  This should more correctly
tell how much time SlimNav restoration adds.

Bug: 1005044
Change-Id: I35fee36bb50ec627d7455d6215669a92a2b4bc6e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1808355
Auto-Submit: Justin Cohen <justincohen@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Commit-Queue: Justin Cohen <justincohen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#697757}

ios/web/navigation/crw_wk_navigation_handler.mm

@@ -568,6 +568,8 @@ void ReportOutOfSyncURLInDidStartProvisionalNavigation(
     }
 
     self.webStateImpl->OnNavigationStarted(context);
+    self.webStateImpl->GetNavigationManagerImpl().OnNavigationStarted(
+        webViewURL);
     return;
   }
 
@@ -618,8 +620,7 @@ void ReportOutOfSyncURLInDidStartProvisionalNavigation(
     return;
   }
 
-  self.webStateImpl->GetNavigationManagerImpl()
-      .OnRendererInitiatedNavigationStarted(webViewURL);
+  self.webStateImpl->GetNavigationManagerImpl().OnNavigationStarted(webViewURL);
 
   // When a client-side redirect occurs while an interstitial warning is
   // displayed, clear the warning and its navigation item, so that a new

ios/web/navigation/legacy_navigation_manager_impl.h

@@ -36,7 +36,7 @@ class LegacyNavigationManagerImpl : public NavigationManagerImpl {
   void SetSessionController(CRWSessionController* session_controller) override;
   void InitializeSession() override;
   void OnNavigationItemsPruned(size_t pruned_item_count) override;
-  void OnRendererInitiatedNavigationStarted(const GURL& url) override;
+  void OnNavigationStarted(const GURL& url) override;
   void OnNavigationItemCommitted() override;
   CRWSessionController* GetSessionController() const override;
   void AddTransientItem(const GURL& url) override;

ios/web/navigation/legacy_navigation_manager_impl.mm

@@ -59,8 +59,7 @@ void LegacyNavigationManagerImpl::OnNavigationItemCommitted() {
   delegate_->OnNavigationItemCommitted(item);
 }
 
-void LegacyNavigationManagerImpl::OnRendererInitiatedNavigationStarted(
-    const GURL& url) {}
+void LegacyNavigationManagerImpl::OnNavigationStarted(const GURL& url) {}
 
 CRWSessionController* LegacyNavigationManagerImpl::GetSessionController()
     const {

ios/web/navigation/navigation_manager_impl.h

@@ -94,8 +94,8 @@ class NavigationManagerImpl : public NavigationManager {
   virtual void OnNavigationItemsPruned(size_t pruned_item_count) = 0;
   virtual void OnNavigationItemCommitted() = 0;
 
-  // Called when renderer-initiated navigation has started.
-  virtual void OnRendererInitiatedNavigationStarted(const GURL& url) = 0;
+  // Called when a navigation has started.
+  virtual void OnNavigationStarted(const GURL& url) = 0;
 
   // Prepares for the deletion of WKWebView such as caching necessary data.
   virtual void DetachFromWebView();

ios/web/navigation/navigation_manager_impl_unittest.mm

@@ -1881,8 +1881,7 @@ TEST_P(NavigationManagerTest, ReloadWithUserAgentTypeOnIntenalUrl) {
       ->GetPendingItemInCurrentOrRestoredSession()
       ->SetVirtualURL(virtual_url);
   [mock_wk_list_ setCurrentURL:base::SysUTF8ToNSString(url.spec())];
-  navigation_manager()->OnRendererInitiatedNavigationStarted(
-      GURL("http://www.1.com/virtual"));
+  navigation_manager()->OnNavigationStarted(GURL("http://www.1.com/virtual"));
 
   navigation_manager()->ReloadWithUserAgentType(UserAgentType::DESKTOP);
 
@@ -2089,14 +2088,14 @@ TEST_P(NavigationManagerTest, Restore) {
     EXPECT_TRUE(pending_url.SchemeIsFile());
     EXPECT_EQ("restore_session.html", pending_url.ExtractFileName());
     EXPECT_EQ("http://www.url.com/0", pending_item->GetVirtualURL());
+    navigation_manager()->OnNavigationStarted(pending_url);
 
     // Simulate the end effect of loading the restore session URL in web view.
     pending_item->SetURL(urls[1]);
     [mock_wk_list_ setCurrentURL:@"http://www.url.com/1"
                     backListURLs:@[ @"http://www.url.com/0" ]
                  forwardListURLs:@[ @"http://www.url.com/2" ]];
-    navigation_manager()->OnRendererInitiatedNavigationStarted(
-        GURL("http://www.url.com/2"));
+    navigation_manager()->OnNavigationStarted(GURL("http://www.url.com/2"));
   }
 
   ASSERT_TRUE(WaitUntilConditionOrTimeout(kWaitForPageLoadTimeout, ^{

ios/web/navigation/wk_based_navigation_manager_impl.h

@@ -94,7 +94,7 @@ class WKBasedNavigationManagerImpl : public NavigationManagerImpl {
   void InitializeSession() override;
   void OnNavigationItemsPruned(size_t pruned_item_count) override;
   void OnNavigationItemCommitted() override;
-  void OnRendererInitiatedNavigationStarted(const GURL& url) override;
+  void OnNavigationStarted(const GURL& url) override;
   void DetachFromWebView() override;
   CRWSessionController* GetSessionController() const override;
   void AddTransientItem(const GURL& url) override;

ios/web/navigation/wk_based_navigation_manager_impl.mm

@@ -98,14 +98,17 @@ void WKBasedNavigationManagerImpl::OnNavigationItemCommitted() {
   }
 }
 
-void WKBasedNavigationManagerImpl::OnRendererInitiatedNavigationStarted(
-    const GURL& url) {
-  if (!wk_navigation_util::IsRestoreSessionUrl(url) &&
-      is_restore_session_in_progress_) {
-    // Session restoration navigations are rendered-initiated.
+void WKBasedNavigationManagerImpl::OnNavigationStarted(const GURL& url) {
+  if (!is_restore_session_in_progress_)
+    return;
 
+  GURL target_url;
+  if (wk_navigation_util::IsRestoreSessionUrl(url) &&
+      !web::wk_navigation_util::ExtractTargetURL(url, &target_url)) {
+    restoration_timer_ = std::make_unique<base::ElapsedTimer>();
+  } else if (!wk_navigation_util::IsRestoreSessionUrl(url)) {
     is_restore_session_in_progress_ = false;
-
+    DCHECK(restoration_timer_);
     UMA_HISTOGRAM_TIMES(kRestoreNavigationTime, restoration_timer_->Elapsed());
     restoration_timer_.reset();
 
@@ -715,7 +718,6 @@ void WKBasedNavigationManagerImpl::UnsafeRestore(
   // committed item, because a restored session has no pending or transient
   // item.
   is_restore_session_in_progress_ = true;
-  restoration_timer_ = std::make_unique<base::ElapsedTimer>();
   if (last_committed_item_index > -1)
     restored_visible_item_ = std::move(items[last_committed_item_index]);
 

ios/web/web_state/web_state_unittest.mm

@@ -607,6 +607,7 @@ TEST_P(WebStateTest, RestorePageTitles) {
   CRWSessionStorage* session_storage = [[CRWSessionStorage alloc] init];
   session_storage.itemStorages = item_storages;
   auto web_state = WebState::CreateWithStorageSession(params, session_storage);
+  web_state->SetKeepRenderProcessAlive(true);
   NavigationManager* navigation_manager = web_state->GetNavigationManager();
   // TODO(crbug.com/873729): The session will not be restored until
   // LoadIfNecessary call. Fix the bug and remove extra call.