[ios] EarlGrey test for PDF Mime type.

ios/web/public/test/earl_grey/web_view_matchers.h

 // Copyright 2016 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 <string>
 
 #import <EarlGrey/EarlGrey.h>
 
 #import "ios/web/public/web_state/web_state.h"
 
 namespace web {
 
 // Shorthand for GREYMatchers::matcherForWebViewContainingText:inWebState.
 id<GREYMatcher> webViewContainingText(const std::string& text,
                                       web::WebState* webState);
 
 // Shorthand for GREYMatchers::matcherForWebWithCSSSelector:inWebState.
 id<GREYMatcher> webViewCssSelector(const std::string& selector,
                                    web::WebState* webState);
 
 // Shorthand for GREYMatchers::matcherForWebViewScrollViewInWebState.
 id<GREYMatcher> webViewScrollView(web::WebState* webState);
 
+// Shorthand for GREYMatchers::matcherForWebViewMIMETYPE:inWebState.
+id<GREYMatcher> webViewMimeType(const std::string& mime_type,
+                                web::WebState* webState);
+
 }  // namespace web
 
 @interface GREYMatchers (WebViewAdditions)
 
 // Matcher for WKWebView containing |text|.
 + (id<GREYMatcher>)matcherForWebViewContainingText:(const std::string&)text
                                         inWebState:(web::WebState*)webState;
 
 // Matcher for WKWebView containing an html element which matches |selector|.
 + (id<GREYMatcher>)matcherForWebWithCSSSelector:(const std::string&)selector
                                      inWebState:(web::WebState*)webState;
 
 // Matcher for WKWebView's scroll view.
 + (id<GREYMatcher>)matcherForWebViewScrollViewInWebState:
     (web::WebState*)webState;
 
+// Matcher for WKWebView with given MIME type.
++ (id<GREYMatcher>)matcherForWebViewMIMEType:(const std::string&)MIMEType
+                                  inWebState:(web::WebState*)webState;
+
 @end