Add shortcut keys to ui scaling

ash/display/display_manager.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/display/display_manager.h"
 
 #include <set>
 #include <string>
 #include <vector>
 
@@ skipping 84 matching lines @@
 
 DisplayManager::~DisplayManager() {
 }
 
 // static
 void DisplayManager::CycleDisplay() {
   Shell::GetInstance()->display_manager()->CycleDisplayImpl();
 }
 
 // static
-void DisplayManager::ToggleDisplayScale() {
+void DisplayManager::ToggleDisplayScaleFactor() {
   Shell::GetInstance()->display_manager()->ScaleDisplayImpl();
 }
 
 bool DisplayManager::IsActiveDisplay(const gfx::Display& display) const {
   for (DisplayList::const_iterator iter = displays_.begin();
        iter != displays_.end(); ++iter) {
     if ((*iter).id() == display.id())
       return true;
   }
   return false;
@@ skipping 50 matching lines @@
   DisplayInfoList display_info_list;
   for (DisplayList::const_iterator iter = displays_.begin();
        iter != displays_.end(); ++iter) {
     display_info_list.push_back(GetDisplayInfo(*iter));
   }
   UpdateDisplays(display_info_list);
 }
 
 void DisplayManager::SetDisplayRotation(int64 display_id,
                                         gfx::Display::Rotation rotation) {
+  if (!IsDisplayRotationEnabled())
+    return;
   DisplayInfoList display_info_list;
   for (DisplayList::const_iterator iter = displays_.begin();
        iter != displays_.end(); ++iter) {
     DisplayInfo info = GetDisplayInfo(*iter);
     if (info.id() == display_id)
       info.set_rotation(rotation);
     display_info_list.push_back(info);
   }
   UpdateDisplays(display_info_list);
 }
 
+void DisplayManager::SetDisplayUIScale(int64 display_id,
+                                       float ui_scale) {
+  if (!IsDisplayUIScalingEnabled())
+    return;
+  DisplayInfoList display_info_list;
+  for (DisplayList::const_iterator iter = displays_.begin();
+       iter != displays_.end(); ++iter) {
+    DisplayInfo info = GetDisplayInfo(*iter);
+    if (info.id() == display_id)
+      info.set_ui_scale(ui_scale);
+    display_info_list.push_back(info);
+  }
+  UpdateDisplays(display_info_list);
+}
+
+
+bool DisplayManager::IsDisplayRotationEnabled() const {
+  static bool enabled = !CommandLine::ForCurrentProcess()->
+      HasSwitch(switches::kAshDisableDisplayRotation);
+  return enabled;
+}
+
+bool DisplayManager::IsDisplayUIScalingEnabled() const {
+  static bool enabled = !CommandLine::ForCurrentProcess()->
+      HasSwitch(switches::kAshDisableUIScaling);
+  if (!enabled)
+    return false;
+  // UI Scaling is effective only when the internal display has
+  // 2x density (currently Pixel).
+  int64 display_id = gfx::Display::InternalDisplayId();
+#if defined(OS_CHROMEOS)
+  // On linux desktop, allow ui scaling on the first dislpay.
+  if (!base::chromeos::IsRunningOnChromeOS())
+    display_id = Shell::GetInstance()->display_manager()->first_display_id();
+#endif
+  return GetDisplayForId(display_id).device_scale_factor() == 2.0f;
+}
+
 gfx::Insets DisplayManager::GetOverscanInsets(int64 display_id) const {
   std::map<int64, DisplayInfo>::const_iterator it =
       display_info_.find(display_id);
   return (it != display_info_.end()) ?
       it->second.overscan_insets_in_dip() : gfx::Insets();
 }
 
 void DisplayManager::OnNativeDisplaysChanged(
     const std::vector<DisplayInfo>& updated_displays) {
   if (updated_displays.empty()) {
@@ skipping 408 matching lines @@
   // always (0,0) and the secondary display's bounds will be updated
   // by |DisplayController::UpdateDisplayBoundsForLayout|.
   new_display.SetScaleAndBounds(
       display_info.device_scale_factor(), gfx::Rect(bounds_in_pixel.size()));
   new_display.set_rotation(display_info.rotation());
   return new_display;
 }
 
 }  // namespace internal
 }  // namespace ash