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..1b426777de74e2e0e2f65c40d0fc0b1be3a59a35
--- /dev/null
+++ b/ios/web/web_state/js/crw_js_post_request_loader.h
@@ -0,0 +1,27 @@
+// 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/WKWebView.h>

[Eugene But (OOO till 7-30), 2015/12/02 17:06:15]

s/<WebKit/WKWebView.h>/<WebKit/WebKit.h>

https://google.github.io/styleguide/objcguide.xml?showone=Use_Root_Frameworks...

[stkhapugin, 2015/12/03 15:43:01]

Done.

+
+@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. If an error occurs, |errorBlock| is called. If the load
+// was successfull, the optional |successBlock| is called.
+- (void)loadPOSTRequest:(NSURLRequest*)request
+              inWebView:(WKWebView*)webView
+          messageRouter:(CRWWKScriptMessageRouter*)messageRouter
+             errorBlock:(void (^)(NSError*))errorBlock

[Eugene But (OOO till 7-30), 2015/12/02 17:06:15]

There should be only one completion handler for both success and failure cases.
For success case NSError is nil.

- (void)loadPOSTRequest:(NSURLRequest*)request
....
completionHandler:(void (^)(NSError*))completionHandler

Having 2 blocks is error prone, lead to code duplication and makes formatting
uglier.

[stkhapugin, 2015/12/03 15:43:01]

Done.

+           successBlock:(void (^)())successBlock;
+
+@end
+
+#endif  // IOS_WEB_WEB_STATE_JS_CRW_JS_POST_REQUEST_LOADER_H_