[WIP] make GURL::path() return a StringPiece

ios/web/webui/crw_web_ui_manager_unittest.mm

 // Copyright 2015 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 "ios/web/webui/crw_web_ui_manager.h"
 
 #include <memory>
 
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
@@ skipping 61 matching lines @@
         completion_handler_([completion_handler copy]) {}
 
   void Start() override {
     if (url_.spec() == kFaviconUrl) {
       base::FilePath favicon_path;
       ASSERT_TRUE(PathService::Get(base::DIR_SOURCE_ROOT, &favicon_path));
       favicon_path = favicon_path.AppendASCII(kFaviconPath);
       NSData* favicon = [NSData
           dataWithContentsOfFile:base::SysUTF8ToNSString(favicon_path.value())];
       completion_handler_.get()(favicon, this);
-    } else if (url_.path().find(kMojoModuleName) != std::string::npos) {
+    } else if (url_.path().find(kMojoModuleName) != base::StringPiece::npos) {
       completion_handler_.get()(
           [kMojoModule dataUsingEncoding:NSUTF8StringEncoding], this);
 
     } else if (url_.scheme().find("test") != std::string::npos) {
       completion_handler_.get()([kHtml dataUsingEncoding:NSUTF8StringEncoding],
                                 this);
     } else {
       NOTREACHED();
     }
   }
@@ skipping 102 matching lines @@
       "%s__crWeb.webUIModuleLoadNotifier.moduleLoadCompleted(\"%s\", \"%s\");",
       base::SysNSStringToUTF8(kMojoModule).c_str(), kMojoModuleName,
       kTestLoadId);
 
   EXPECT_CALL(*web_state_impl_,
               ExecuteJavaScript(base::UTF8ToUTF16(expected_javascript)));
   web_state_impl_->OnScriptCommandReceived("webui.loadMojo", message,
                                            GURL(kTestWebUIUrl), false);
 }
 }  // namespace web