Add NavigationContextImpl::IsLoadingHtml.

This boolean will be true for loadHTMLString: navigations.

-[CRWWebController setDocumentURL:] will have a DCHECK when new document
URL does not match last committed URL in WKBasedNavigationManager. This
DCHECK will help to diagnose possible URL spoofing bugs in Slim
Navigation feature.

For loadHTMLString: the URLs will not match, which is not a problem
because loadHTMLString: are only used in tests and error pages.

Bug: 876077
Cq-Include-Trybots: luci.chromium.try:ios-simulator-full-configs;master.tryserver.chromium.mac:ios-simulator-cronet
Change-Id: Iae163faf7f5cf90d5bb0e48a191786be2e1d8ee6
Reviewed-on: https://chromium-review.googlesource.com/1182313Reviewed-by: Mike Dougherty <michaeldo@chromium.org>
Commit-Queue: Mike Dougherty <michaeldo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#584740}

ios/web/web_state/navigation_context_impl.h

@@ -68,11 +68,18 @@ class NavigationContextImpl : public NavigationContext {
   void SetWKNavigationType(WKNavigationType wk_navigation_type);
   WKNavigationType GetWKNavigationType() const;
 
-  // true if this navigation context is a loadHTMLString: navigation used to
-  // load Error page into web view.
+  // true if this navigation context is a -[WKWebView loadHTMLString:baseURL:]
+  // navigation used to load Error page into web view. IsLoadingErrorPage() and
+  // IsLoadingHtmlString() are mutually exclusive.
   bool IsLoadingErrorPage() const;
   void SetLoadingErrorPage(bool is_loading_error_page);
 
+  // true if this navigation context is a -[WKWebView loadHTMLString:baseURL:]
+  // navigation. IsLoadingErrorPage() and IsLoadingHtmlString() are mutually
+  // exclusive.
+  bool IsLoadingHtmlString() const;
+  void SetLoadingHtmlString(bool is_loading_html);
+
   // true if this navigation context is a placeholder navigation associated with
   // a native view URL and the native content is already presented.
   bool IsNativeContentPresented() const;
@@ -100,6 +107,7 @@ class NavigationContextImpl : public NavigationContext {
   int navigation_item_unique_id_ = -1;
   WKNavigationType wk_navigation_type_ = WKNavigationTypeOther;
   bool is_loading_error_page_ = false;
+  bool is_loading_html_string_ = false;
   bool is_native_content_presented_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(NavigationContextImpl);

ios/web/web_state/navigation_context_impl.mm

@@ -158,6 +158,14 @@ void NavigationContextImpl::SetLoadingErrorPage(bool is_loading_error_page) {
   is_loading_error_page_ = is_loading_error_page;
 }
 
+bool NavigationContextImpl::IsLoadingHtmlString() const {
+  return is_loading_html_string_;
+}
+
+void NavigationContextImpl::SetLoadingHtmlString(bool is_loading_html_string) {
+  is_loading_html_string_ = is_loading_html_string;
+}
+
 bool NavigationContextImpl::IsNativeContentPresented() const {
   return is_native_content_presented_;
 }

ios/web/web_state/ui/crw_web_controller.mm

@@ -4020,6 +4020,7 @@ registerLoadRequestForURL:(const GURL&)requestURL
                        sameDocumentNavigation:NO
                                hasUserGesture:true];
   }
+  context->SetLoadingHtmlString(true);
   [_navigationStates setContext:std::move(context) forNavigation:navigation];
 }