Adds support for new-tab targeted loads initiated from the renderer.

mash/webtest/webtest.cc

 // 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 "mash/webtest/webtest.h"
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "base/strings/string16.h"
@@ skipping 81 matching lines @@
       content_area_ = window->window_tree()->NewWindow(nullptr);
       window->AddChild(content_area_);
 
       mus::mojom::WindowTreeClientPtr client;
       view_->GetWindowTreeClient(GetProxy(&client));
       content_area_->Embed(std::move(client));
     }
   }
 
   // navigation::mojom::ViewClient:
+  void OpenURL(navigation::mojom::OpenURLParamsPtr params) override {}
   void LoadingStateChanged(bool is_loading) override {}
   void NavigationStateChanged(const GURL& url,
                               const mojo::String& title,
                               bool can_go_back,
                               bool can_go_forward) override {
     current_title_ = base::UTF8ToUTF16(title.get());
     GetWidget()->UpdateWindowTitle();
   }
   void LoadProgressChanged(double progress) override {}
   void UpdateHoverURL(const GURL& url) override {}
@@ skipping 83 matching lines @@
   AddWindow(window);
 }
 
 void Webtest::Create(shell::Connection* connection,
                      mojom::LaunchableRequest request) {
   bindings_.AddBinding(this, std::move(request));
 }
 
 }  // namespace webtest
 }  // namespace mash