Mojo C++ bindings: switch ios/web mojom targets to use STL types.

ios/web/webui/web_ui_mojo_inttest.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 <memory>
 
 #include "base/run_loop.h"
 #import "base/test/ios/wait_util.h"
 #import "ios/web/public/navigation_manager.h"
 #include "ios/web/public/web_ui_ios_data_source.h"
@@ skipping 31 matching lines @@
       public service_manager::InterfaceFactory<TestUIHandlerMojo> {
  public:
   TestUIHandler() {}
   ~TestUIHandler() override {}
 
   // Returns true if "fin" has been received.
   bool IsFinReceived() { return fin_received_; }
 
   // TestUIHandlerMojo overrides.
   void SetClientPage(TestPagePtr page) override { page_ = std::move(page); }
-  void HandleJsMessage(const mojo::String& message) override {
-    if (message.get() == "syn") {
+  void HandleJsMessage(const std::string& message) override {
+    if (message == "syn") {
       // Received "syn" message from WebUI page, send "ack" as reply.
       DCHECK(!syn_received_);
       DCHECK(!fin_received_);
       syn_received_ = true;
       NativeMessageResultMojoPtr result(NativeMessageResultMojo::New());
-      result->message = mojo::String::From("ack");
+      result->message = "ack";
       page_->HandleNativeMessage(std::move(result));
-    } else if (message.get() == "fin") {
+    } else if (message == "fin") {
       // Received "fin" from the WebUI page in response to "ack".
       DCHECK(syn_received_);
       DCHECK(!fin_received_);
       fin_received_ = true;
     } else {
       NOTREACHED();
     }
   }
 
  private:
@@ skipping 87 matching lines @@
   web_state()->GetNavigationManager()->LoadURLWithParams(load_params);
 
   // Wait until |TestUIHandler| receives "ack" message from WebUI page.
   base::test::ios::WaitUntilCondition(^{
     base::RunLoop().RunUntilIdle();
     return test_ui_handler()->IsFinReceived();
   });
 }
 
 }  // namespace web