Adds support for POST request with bodies on WKWebView.

ios/web/web_state/js/crw_js_post_request_loader.h

Index: ios/web/web_state/js/crw_js_post_request_loader.h
diff --git a/ios/web/web_state/js/crw_js_post_request_loader.h b/ios/web/web_state/js/crw_js_post_request_loader.h
new file mode 100644
index 0000000000000000000000000000000000000000..f2153987c57c14a45d83de9d93deb5ee77b8e6ec
--- /dev/null
+++ b/ios/web/web_state/js/crw_js_post_request_loader.h
@@ -0,0 +1,26 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef IOS_WEB_WEB_STATE_JS_CRW_JS_POST_REQUEST_LOADER_H_
+#define IOS_WEB_WEB_STATE_JS_CRW_JS_POST_REQUEST_LOADER_H_
+
+#import <WebKit/WebKit.h>
+
+@class CRWWKScriptMessageRouter;
+
+// Class to load POST requests in a provided web view via JavaScript.
+@interface CRWJSPOSTRequestLoader : NSObject
+
+// Asynchronously loads a POST |request| in provided |webView|.
+// It temporarily installs JavaScript message routers with |messageRouter| to
+// handle HTTP errors. The |completionBlock| is called once the request has been
+// executed. In case of successful request, the passed error is nil.

[Eugene But (OOO till 7-30), 2015/12/03 16:51:42]

Add: |completionBlock| can not be null.

[stkhapugin, 2015/12/03 17:51:02]

Done.

+- (void)loadPOSTRequest:(NSURLRequest*)request
+              inWebView:(WKWebView*)webView
+          messageRouter:(CRWWKScriptMessageRouter*)messageRouter
+        completionBlock:(void (^)(NSError*))completionBlock;

[Eugene But (OOO till 7-30), 2015/12/03 16:51:42]

Optional NIT s/completionBlock/completionHandler sounds more modern.

[stkhapugin, 2015/12/03 17:51:02]

Done.

+
+@end
+
+#endif  // IOS_WEB_WEB_STATE_JS_CRW_JS_POST_REQUEST_LOADER_H_