Split up ios/web:test_support.

ios/web/shell/test/plugin_placeholder_egtest.mm

 // 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.
 
 #include <map>
 #include <string>
 
 #import <EarlGrey/EarlGrey.h>
 
 #include "base/strings/stringprintf.h"
 #import "base/test/ios/wait_util.h"
-#import "ios/web/public/test/http_server.h"
-#include "ios/web/public/test/http_server_util.h"
+#import "ios/web/public/test/http_server/http_server.h"
+#include "ios/web/public/test/http_server/http_server_util.h"
 #import "ios/web/shell/test/earl_grey/shell_earl_grey.h"
 #import "ios/web/shell/test/earl_grey/shell_matchers.h"
 #import "ios/web/shell/test/earl_grey/web_shell_test_case.h"
 #include "url/gurl.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
 using web::WebViewContainingText;
@@ skipping 179 matching lines @@
   LoadPage(page);
 
   // Verify that placeholder image is not displayed.
   [[EarlGrey selectElementWithMatcher:WebViewContainingText(kPageDescription)]
       assertWithMatcher:grey_notNil()];
   [[EarlGrey selectElementWithMatcher:WebViewCssSelector("img")]
       assertWithMatcher:grey_nil()];
 }
 
 @end