Reland of place string::find(prefix) == 0 pattern with base::StartsWith().

chrome/browser/apps/guest_view/web_view_browsertest.cc

 // Copyright 2013 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 <queue>
 #include <set>
 #include <utility>
 
 #include "base/callback_helpers.h"
 #include "base/files/file_util.h"
@@ skipping 2337 matching lines @@
 const char kDownloadPathPrefix[] = "/download_cookie_isolation_test";
 
 // EmbeddedTestServer request handler for use with DownloadCookieIsolation test.
 // Responds with the next status code in |status_codes| if the 'Cookie' header
 // sent with the request matches the query() part of the URL. Otherwise, fails
 // the request with an HTTP 403. The body of the response is the value of the
 // Cookie header.
 std::unique_ptr<net::test_server::HttpResponse> HandleDownloadRequestWithCookie(
     std::queue<net::HttpStatusCode>* status_codes,
     const net::test_server::HttpRequest& request) {
-  if (request.relative_url.find(kDownloadPathPrefix) != 0) {
+  if (!base::StartsWith(request.relative_url, kDownloadPathPrefix,
+                        base::CompareCase::SENSITIVE)) {
     return std::unique_ptr<net::test_server::HttpResponse>();
   }
 
   std::string cookie_to_expect = request.GetURL().query();
   const auto cookie_header_it = request.headers.find("cookie");
   std::unique_ptr<net::test_server::BasicHttpResponse> response;
 
   // Return a 403 if there's no cookie or if the cookie doesn't match.
   if (cookie_header_it == request.headers.end() ||
       cookie_header_it->second != cookie_to_expect) {
@@ skipping 1217 matching lines @@
   gfx::Point embedder_origin =
       GetEmbedderWebContents()->GetContainerBounds().origin();
   guest_rect.Offset(-embedder_origin.x(), -embedder_origin.y());
 
   // Generate and send synthetic touch event.
   content::SimulateTouchPressAt(GetEmbedderWebContents(),
                                 guest_rect.CenterPoint());
   EXPECT_TRUE(aura_webview->HasFocus());
 }
 #endif