Update to Chromium revision 6e53600d (#386251)

- Remove |accept_lang| parameter from CefJSDialogHandler::OnJSDialog
  and CefFormatUrlForSecurityDisplay (see https://crbug.com/336973#c36).
- Remove remaining NPAPI-related code including functions from
  cef_web_plugin.h (see https://crbug.com/493212#c55).
- Mac: 10.7+ deployment target is now required for client applications.
- Mac: Remove CefBrowserHost::SetWindowVisibility (issue #1375). No
  replacement is required for windowed rendering. Use WasHidden for
  off-screen rendering.
- Windows: Visual Studio 2015 Update 2 is now required when building
  CEF/Chromium.

libcef/browser/views/browser_platform_delegate_views.cc

@@ -51,7 +51,7 @@ class PopupWindowDelegate : public CefWindowDelegate {
 }  // namespace
 
 CefBrowserPlatformDelegateViews::CefBrowserPlatformDelegateViews(
-    scoped_ptr<CefBrowserPlatformDelegateNative> native_delegate,
+    std::unique_ptr<CefBrowserPlatformDelegateNative> native_delegate,
     CefRefPtr<CefBrowserViewImpl> browser_view)
     : native_delegate_(std::move(native_delegate)),
       browser_view_(browser_view) {
@@ -257,17 +257,17 @@ CefEventHandle CefBrowserPlatformDelegateViews::GetEventHandle(
   return native_delegate_->GetEventHandle(event);
 }
 
-scoped_ptr<CefFileDialogRunner>
+std::unique_ptr<CefFileDialogRunner>
     CefBrowserPlatformDelegateViews::CreateFileDialogRunner() {
   return native_delegate_->CreateFileDialogRunner();
 }
 
-scoped_ptr<CefJavaScriptDialogRunner>
+std::unique_ptr<CefJavaScriptDialogRunner>
     CefBrowserPlatformDelegateViews::CreateJavaScriptDialogRunner() {
   return native_delegate_->CreateJavaScriptDialogRunner();
 }
 
-scoped_ptr<CefMenuRunner> CefBrowserPlatformDelegateViews::CreateMenuRunner() {
+std::unique_ptr<CefMenuRunner> CefBrowserPlatformDelegateViews::CreateMenuRunner() {
   return make_scoped_ptr(new CefMenuRunnerViews(browser_view_.get()));
 }