Fixes document type detection on iOS 9.

ios/web/web_state/ui/crw_web_controller.mm

 // Copyright 2012 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.
 
 #import "ios/web/web_state/ui/crw_web_controller.h"
 
 #import <objc/runtime.h>
 #include <cmath>
 
 #include "base/ios/block_types.h"
@@ skipping 802 matching lines @@
 }
 
 - (BOOL)isViewAlive {
   return [self.containerView isViewAlive];
 }
 
 - (BOOL)contentIsHTML {
   return [self webViewDocumentType] == web::WEB_VIEW_DOCUMENT_TYPE_HTML;
 }
 
+- (web::WebViewDocumentType)documentTypeFromMIMEType:(NSString*)MIMEType {

[Eugene But (OOO till 7-30), 2015/11/19 16:29:01]

NIT: Please try keeping the same order for interface and implementation methods
(I know we are inconsistent with this). 

F.e. if in the header |documentTypeFromMIMEType:| is placed after |foo|, then in
the implementation |documentTypeFromMIMEType:| should also be placed after
|foo|.

[stkhapugin, 2015/11/20 10:50:43]

Done.

+  if ([MIMEType isEqualToString:@"text/html"] ||
+      [MIMEType isEqualToString:@"application/xhtml+xml"] ||
+      [MIMEType isEqualToString:@"application/xml"]) {
+    return web::WEB_VIEW_DOCUMENT_TYPE_HTML;
+  }
+
+  return web::WEB_VIEW_DOCUMENT_TYPE_GENERIC;
+}
+
 // Stop doing stuff, especially network stuff. Close the request tracker.
 - (void)terminateNetworkActivity {
   DCHECK(!_isHalted);
   _isHalted = YES;
 
   // Cancel all outstanding perform requests, and clear anything already queued
   // (since this may be called from within the handling loop) to prevent any
   // asynchronous JavaScript invocation handling from continuing.
   [NSObject cancelPreviousPerformRequestsWithTarget:self];
   _webStateImpl->CloseRequestTracker();
@@ skipping 2987 matching lines @@
   if (!_externalRequest || !_externalRequest->window_name)
     return @"";
   return _externalRequest->window_name;
 }
 
 - (void)resetExternalRequest {
   _externalRequest.reset();
 }
 
 @end