Avoid repeated command-line checks for forced DPI scale

ui/gfx/display.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 "ui/gfx/display.h"
 
 #include <algorithm>
 
 #include "base/command_line.h"
 #include "base/logging.h"
@@ skipping 33 matching lines @@
 
 // static
 float Display::GetForcedDeviceScaleFactor() {
   static const float kForcedDeviceScaleFactor =
       GetForcedDeviceScaleFactorImpl();
   return kForcedDeviceScaleFactor;
 }
 
 //static
 bool Display::HasForceDeviceScaleFactor() {
-  return HasForceDeviceScaleFactorImpl();
+  static const bool kHasForceDeviceScaleFactor =
+      HasForceDeviceScaleFactorImpl();
+  return kHasForceDeviceScaleFactor;
 }
 
 Display::Display()
     : id_(kInvalidDisplayID),
       device_scale_factor_(GetForcedDeviceScaleFactor()),
       rotation_(ROTATE_0),
       touch_support_(TOUCH_SUPPORT_UNKNOWN) {
 }
 
 Display::Display(int64 id)
@@ skipping 81 matching lines @@
 
 int64 Display::InternalDisplayId() {
   return internal_display_id_;
 }
 
 void Display::SetInternalDisplayId(int64 internal_display_id) {
   internal_display_id_ = internal_display_id;
 }
 
 }  // namespace gfx