Fix invalid NSError initializations.

Initialize NSError with the designated initializer to prevent the
following message from being printing to the console.

    -[NSError init] called; this results in an invalid NSError instance.
    It will raise an exception in a future release. Please call
    errorWithDomain:code:userInfo: or initWithDomain:code:userInfo:.
    This message shown only once.

Bug: None
Cq-Include-Trybots: luci.chromium.try:ios-simulator-full-configs;master.tryserver.chromium.mac:ios-simulator-cronet
Change-Id: I94ac7664f7254126a5e2095d7c22c76497615c04
Reviewed-on: https://chromium-review.googlesource.com/1110490Reviewed-by: Eugene But <eugenebut@chromium.org>
Commit-Queue: Mike Dougherty <michaeldo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#569429}

ios/web/web_state/navigation_context_impl_unittest.mm

@@ -160,7 +160,7 @@ TEST_F(NavigationContextImplTest, Setters) {
   EXPECT_EQ(WKNavigationTypeOther, context->GetWKNavigationType());
 
   // SetErrorPage
-  NSError* error = [[NSError alloc] init];
+  NSError* error = [[NSError alloc] initWithDomain:@"" code:0 userInfo:nil];
   context->SetError(error);
   EXPECT_EQ(new_url, context->GetUrl());
   EXPECT_TRUE(context->IsSameDocument());

ios/web/web_state/ui/crw_wk_navigation_states_unittest.mm

@@ -122,7 +122,7 @@ TEST_F(CRWWKNavigationStatesTest, Context) {
           nullptr /*web_state*/, GURL(kTestUrl2), /*has_user_gesture=*/false,
           ui::PageTransition::PAGE_TRANSITION_GENERATED,
           /*is_renderer_initiated=*/true);
-  NSError* error = [[NSError alloc] init];
+  NSError* error = [[NSError alloc] initWithDomain:@"" code:0 userInfo:nil];
   context2->SetError(error);
   [states_ setContext:std::move(context2) forNavigation:navigation1_];
   EXPECT_FALSE([states_ contextForNavigation:navigation2_]);