mus: Introduce high-contrast mode in mus.

ash/sysui/shell_delegate_mus.cc

Index: ash/sysui/shell_delegate_mus.cc
diff --git a/ash/sysui/shell_delegate_mus.cc b/ash/sysui/shell_delegate_mus.cc
index 8cf896b36b88cd181c747df799be8de66cf0b238..e552096718ab48281c68a506fbebceb3f807139b 100644
--- a/ash/sysui/shell_delegate_mus.cc
+++ b/ash/sysui/shell_delegate_mus.cc
@@ -17,14 +17,42 @@
 #include "base/memory/ptr_util.h"
 #include "base/strings/string16.h"
 #include "components/user_manager/user_info_impl.h"
+#include "services/shell/public/cpp/connector.h"
+#include "services/ui/public/interfaces/accessibility_manager.mojom.h"
 #include "ui/app_list/presenter/app_list_presenter.h"
 #include "ui/gfx/image/image.h"
+#include "ui/views/mus/window_manager_connection.h"
 
 namespace ash {
 namespace sysui {
 
 namespace {
 
+class AccessibilityDelegateMus : public DefaultAccessibilityDelegate {
+ public:
+  AccessibilityDelegateMus() {}
+  ~AccessibilityDelegateMus() override {}
+
+ private:
+  ui::mojom::AccessibilityManager* a11y_manager() {
+    if (!a11y_manager_ptr_.is_bound()) {
+      views::WindowManagerConnection::Get()->connector()->ConnectToInterface(
+          "mojo:ui", &a11y_manager_ptr_);
+    }
+    return a11y_manager_ptr_.get();
+  }
+
+  // DefaultAccessibilityDelegate:
+  void ToggleHighContrast() override {
+    DefaultAccessibilityDelegate::ToggleHighContrast();
+    a11y_manager()->SetHighContrastMode(IsHighContrastEnabled());
+  }
+
+  ui::mojom::AccessibilityManagerPtr a11y_manager_ptr_;
+
+  DISALLOW_COPY_AND_ASSIGN(AccessibilityDelegateMus);
+};
+
 class SessionStateDelegateStub : public SessionStateDelegate {
  public:
   SessionStateDelegateStub()
@@ -195,8 +223,7 @@ SessionStateDelegate* ShellDelegateMus::CreateSessionStateDelegate() {
 }
 
 AccessibilityDelegate* ShellDelegateMus::CreateAccessibilityDelegate() {
-  NOTIMPLEMENTED() << " Using the default AccessibilityDelegate implementation";
-  return new DefaultAccessibilityDelegate;
+  return new AccessibilityDelegateMus;
 }
 
 NewWindowDelegate* ShellDelegateMus::CreateNewWindowDelegate() {