Make ExtensionIconSet::ContainsPath use StringPiece.

chrome/renderer/extensions/resource_request_policy.cc

 // Copyright (c) 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.
 
 #include "chrome/renderer/extensions/resource_request_policy.h"
 
 #include "base/logging.h"
 #include "base/strings/stringprintf.h"
 #include "chrome/common/extensions/chrome_manifest_url_handlers.h"
 #include "chrome/common/url_constants.h"
@@ skipping 36 matching lines @@
   if (!extension) {
     // Allow the load in the case of a non-existent extension. We'll just get a
     // 404 from the browser process.
     return true;
   }
 
   // Disallow loading of packaged resources for hosted apps. We don't allow
   // hybrid hosted/packaged apps. The one exception is access to icons, since
   // some extensions want to be able to do things like create their own
   // launchers.
-  std::string resource_root_relative_path =
-      resource_url.path().empty() ? std::string()
-      : resource_url.path().substr(1);
+  base::StringPiece resource_root_relative_path =
+      resource_url.path_piece().empty() ? base::StringPiece()
+                                        : resource_url.path_piece().substr(1);
   if (extension->is_hosted_app() &&
       !IconsInfo::GetIcons(extension)
           .ContainsPath(resource_root_relative_path)) {
     LOG(ERROR) << "Denying load of " << resource_url.spec() << " from "
                << "hosted app.";
     return false;
   }
 
   // Disallow loading of extension resources which are not explicitly listed
   // as web or WebView accessible if the manifest version is 2 or greater.
@@ skipping 38 matching lines @@
           blink::WebConsoleMessage(blink::WebConsoleMessage::LevelError,
                                     blink::WebString::fromUTF8(message)));
       return false;
     }
   }
 
   return true;
 }
 
 }  // namespace extensions