[ios] Retry injection of windowID if it has failed.

windowID injection will fail if WKUserScript has not been injected yet
and __crWeb object is not present. windowID injection is critical for
many features to function and on failure it should be retried.

So far injection failure has been observed only in KIF test.

BUG=628316

Review-Url: https://codereview.chromium.org/2161463002
Cr-Commit-Position: refs/heads/master@{#406146}

ios/web/web_state/ui/crw_web_controller.mm

@@ -2523,9 +2523,21 @@ const NSTimeInterval kSnapshotOverlayTransition = 0.5;
   // an umbrella manager).
   if ([script length]) {
     // Every injection except windowID requires windowID check.
-    if (JSInjectionManagerClass != [CRWJSWindowIdManager class])
+    if (JSInjectionManagerClass != [CRWJSWindowIdManager class]) {
       script = [self scriptByAddingWindowIDCheckForScript:script];
-    web::ExecuteJavaScript(_webView, script, nil);
+      web::ExecuteJavaScript(_webView, script, nil);
+    } else {
+      web::ExecuteJavaScript(_webView, script, ^(id, NSError* error) {
+        // TODO(crbug.com/628832): Refactor retry logic.
+        if (error.code == WKErrorJavaScriptExceptionOccurred) {
+          // This can happen if WKUserScript has not been injected yet.
+          // Retry if that's the case, because windowID injection is critical
+          // for the system to function.
+          [_injectedScriptManagers removeObject:JSInjectionManagerClass];
+          [self injectWindowID];
+        }
+      });
+    }
   }
   [_injectedScriptManagers addObject:JSInjectionManagerClass];
 }