Screen Magnifier: Change keyboard shortcut from [ALT + Scroll] to [CTRL + ALT + Scroll]

ash/magnifier/magnification_controller.cc

 // Copyright (c) 2012 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 "ash/magnifier/magnification_controller.h"
 
 #include "ash/shell.h"
 #include "ash/shell_delegate.h"
 #include "ui/aura/event_filter.h"
 #include "ui/aura/root_window.h"
@@ skipping 418 matching lines @@
 ////////////////////////////////////////////////////////////////////////////////
 // MagnificationControllerImpl: aura::EventFilter implementation
 
 bool MagnificationControllerImpl::PreHandleKeyEvent(aura::Window* target,
                                                     ui::KeyEvent* event) {
   return false;
 }
 
 bool MagnificationControllerImpl::PreHandleMouseEvent(aura::Window* target,
                                                       ui::MouseEvent* event) {
-  if (event->type() == ui::ET_SCROLL && event->IsAltDown()) {
+  if (event->type() == ui::ET_SCROLL &&
+      event->IsAltDown() &
+      event->IsControlDown()) {
     ui::ScrollEvent* scroll_event = static_cast<ui::ScrollEvent*>(event);
     float scale = GetScale();
     scale += scroll_event->y_offset() * kScrollScaleChangeFactor;
     SetScale(scale, true);
     return true;
   }
 
   if (IsMagnified() && event->type() == ui::ET_MOUSE_MOVED) {
     aura::RootWindow* current_root = target->GetRootWindow();
     gfx::Rect root_bounds = current_root->bounds();
@@ skipping 24 matching lines @@
 ////////////////////////////////////////////////////////////////////////////////
 // MagnificationController:
 
 // static
 MagnificationController* MagnificationController::CreateInstance() {
   return new MagnificationControllerImpl();
 }
 
 }  // namespace internal
 }  // namespace ash