Revert of Fixes document type detection on iOS 9.

ios/web/web_state/ui/crw_ui_web_view_web_controller.mm

Index: ios/web/web_state/ui/crw_ui_web_view_web_controller.mm
diff --git a/ios/web/web_state/ui/crw_ui_web_view_web_controller.mm b/ios/web/web_state/ui/crw_ui_web_view_web_controller.mm
index 7c0a4780f1236708eae2e77a6d36b37cc9c1c83b..072b026e1a0f55cc8d8b9363d33d550cd6d0a18f 100644
--- a/ios/web/web_state/ui/crw_ui_web_view_web_controller.mm
+++ b/ios/web/web_state/ui/crw_ui_web_view_web_controller.mm
@@ -4,7 +4,6 @@
 
 #import "ios/web/web_state/ui/crw_ui_web_view_web_controller.h"
 
-#import "base/ios/ios_util.h"
 #import "base/ios/ns_error_util.h"
 #import "base/ios/weak_nsobject.h"
 #include "base/json/json_reader.h"
@@ -551,25 +550,13 @@
   if (!_uiWebView) {
     return web::WEB_VIEW_DOCUMENT_TYPE_GENERIC;
   }
-
-  if (base::ios::IsRunningOnIOS9OrLater()) {
-    // On iOS 9, evaluating '' + document always results in [object
-    // HTMLDocument], even for PDFs. However, document.contentType is properly
-    // defined.
-    NSString* MIMEType = [_uiWebView
-        stringByEvaluatingJavaScriptFromString:@"document.contentType"];
-    return [self documentTypeFromMIMEType:MIMEType];
-  } else {
-    // On iOS 8 and below, document.contentType is always undefined. Use this
-    // instead.
-    NSString* documentType =
-        [_uiWebView stringByEvaluatingJavaScriptFromString:@"'' + document"];
-    if ([documentType isEqualToString:@"[object HTMLDocument]"])
-      return web::WEB_VIEW_DOCUMENT_TYPE_HTML;
-    else if ([documentType isEqualToString:@"[object Document]"])
-      return web::WEB_VIEW_DOCUMENT_TYPE_GENERIC;
-  }
-
+  NSString* documentType =
+      [_uiWebView stringByEvaluatingJavaScriptFromString:
+          @"'' + document"];
+  if ([documentType isEqualToString:@"[object HTMLDocument]"])
+    return web::WEB_VIEW_DOCUMENT_TYPE_HTML;
+  else if ([documentType isEqualToString:@"[object Document]"])
+    return web::WEB_VIEW_DOCUMENT_TYPE_GENERIC;
   return web::WEB_VIEW_DOCUMENT_TYPE_UNKNOWN;
 }