Replace NavigationItemCommitted with DidFinishNavigation in WebTestWithWebState.

NavigationItemCommitted is deprecated and should be removed.
DidFinishNavigation is more general purpose method, which is called when
navigation is committed, replaced or aborted.

Bug: 781534
Change-Id: I77d79970548e4d5291b9953c09490fddb50c6d72
Reviewed-on: https://chromium-review.googlesource.com/c/1406076Reviewed-by: Danyao Wang <danyao@chromium.org>
Commit-Queue: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#622074}

ios/web/public/test/web_test_with_web_state.mm

@@ -134,8 +134,8 @@ void WebTestWithWebState::LoadHtml(NSString* html, const GURL& url) {
     MimeTypeUpdater() = default;
 
     // WebStateObserver overrides:
-    void NavigationItemCommitted(WebState* web_state,
-                                 const LoadCommittedDetails&) override {
+    void DidFinishNavigation(WebState* web_state,
+                             NavigationContext* context) override {
       // loadHTML:forURL: does not notify web view delegate about received
       // response, so web controller does not get a chance to properly update
       // MIME type and it should be set manually after navigation is committed