[ios] Refactored dialogs suppression.

ios/web/web_state/ui/crw_wk_web_view_web_controller.mm

Index: ios/web/web_state/ui/crw_wk_web_view_web_controller.mm
diff --git a/ios/web/web_state/ui/crw_wk_web_view_web_controller.mm b/ios/web/web_state/ui/crw_wk_web_view_web_controller.mm
index 0d481bbf7272a6abd8d98425dabfbaafa0e9dedc..8d79c34c30f7c26fe1b05c46fcc8defb014ff13b 100644
--- a/ios/web/web_state/ui/crw_wk_web_view_web_controller.mm
+++ b/ios/web/web_state/ui/crw_wk_web_view_web_controller.mm
@@ -457,12 +457,6 @@ WKWebViewErrorSource WKWebViewErrorSourceFromError(NSError* error) {
   [super terminateNetworkActivity];
 }
 
-- (void)setPageDialogOpenPolicy:(web::PageDialogOpenPolicy)policy {
-  // TODO(eugenebut): implement dialogs/windows suppression using
-  // WKNavigationDelegate methods where possible.
-  [super setPageDialogOpenPolicy:policy];
-}
-
 - (void)close {
   [_certVerificationController shutDown];
   [super close];
@@ -697,10 +691,6 @@ WKWebViewErrorSource WKWebViewErrorSourceFromError(NSError* error) {
   // Nothing to do.
 }
 
-- (void)setSuppressDialogsWithHelperScript:(NSString*)script {
-  [self evaluateJavaScript:script stringResultHandler:nil];
-}
-
 - (void)applyWebViewScrollZoomScaleFromZoomState:
     (const web::PageZoomState&)zoomState {
   // After rendering a web page, WKWebView keeps the |minimumZoomScale| and
@@ -1215,6 +1205,12 @@ WKWebViewErrorSource WKWebViewErrorSourceFromError(NSError* error) {
       [space.authenticationMethod isEqual:NSURLAuthenticationMethodNTLM] ||
       [space.authenticationMethod isEqual:NSURLAuthenticationMethodHTTPDigest]);
 
+  if (self.suppressDialogs) {
+    [self didSuppressDialog];
+    completionHandler(NSURLSessionAuthChallengeRejectProtectionSpace, nil);
+    return;
+  }
+
   SEL selector = @selector(webController:
          runAuthDialogForProtectionSpace:
                       proposedCredential:
@@ -1981,6 +1977,11 @@ WKWebViewErrorSource WKWebViewErrorSourceFromError(NSError* error) {
     createWebViewWithConfiguration:(WKWebViewConfiguration*)configuration
                forNavigationAction:(WKNavigationAction*)navigationAction
                     windowFeatures:(WKWindowFeatures*)windowFeatures {
+  if (self.suppressDialogs) {
+    [self didSuppressDialog];
+    return nil;
+  }
+
   GURL requestURL = net::GURLWithNSURL(navigationAction.request.URL);
 
   if (![self userIsInteracting]) {
@@ -2016,6 +2017,12 @@ WKWebViewErrorSource WKWebViewErrorSourceFromError(NSError* error) {
     runJavaScriptAlertPanelWithMessage:(NSString*)message
                       initiatedByFrame:(WKFrameInfo*)frame
                      completionHandler:(void(^)())completionHandler {
+  if (self.suppressDialogs) {
+    [self didSuppressDialog];
+    completionHandler();
+    return;
+  }
+
   SEL alertSelector = @selector(webController:
            runJavaScriptAlertPanelWithMessage:
                                    requestURL:
@@ -2035,6 +2042,12 @@ WKWebViewErrorSource WKWebViewErrorSourceFromError(NSError* error) {
                         initiatedByFrame:(WKFrameInfo*)frame
                        completionHandler:
         (void (^)(BOOL result))completionHandler {
+  if (self.suppressDialogs) {
+    [self didSuppressDialog];
+    completionHandler(NO);
+    return;
+  }
+
   SEL confirmationSelector = @selector(webController:
                 runJavaScriptConfirmPanelWithMessage:
                                           requestURL:
@@ -2056,6 +2069,12 @@ WKWebViewErrorSource WKWebViewErrorSourceFromError(NSError* error) {
                          initiatedByFrame:(WKFrameInfo*)frame
                         completionHandler:
         (void (^)(NSString *result))completionHandler {
+  if (self.suppressDialogs) {
+    [self didSuppressDialog];
+    completionHandler(nil);
+    return;
+  }
+
   SEL textInputSelector = @selector(webController:
             runJavaScriptTextInputPanelWithPrompt:
                                       defaultText: