Added 250p scale factor.

ui/base/layout.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/base/layout.h"
 
 #include <algorithm>
 #include <cmath>
 #include <limits>
 
@@ skipping 17 matching lines @@
 
 namespace {
 
 bool ScaleFactorComparator(const ScaleFactor& lhs, const ScaleFactor& rhs){
   return GetScaleForScaleFactor(lhs) < GetScaleForScaleFactor(rhs);
 }
 
 std::vector<ScaleFactor>* g_supported_scale_factors = NULL;
 
 const float kScaleFactorScales[] = {1.0f, 1.0f, 1.25f, 1.33f, 1.4f, 1.5f, 1.8f,
-                                    2.0f, 3.0f};
+                                    2.0f, 2.5f, 3.0f};
 COMPILE_ASSERT(NUM_SCALE_FACTORS == arraysize(kScaleFactorScales),
                kScaleFactorScales_incorrect_size);
 
 }  // namespace
 
 void SetSupportedScaleFactors(
     const std::vector<ui::ScaleFactor>& scale_factors) {
   if (g_supported_scale_factors != NULL)
     delete g_supported_scale_factors;
 
@@ skipping 75 matching lines @@
   gfx::Screen* screen = gfx::Screen::GetScreenFor(view);
   if (screen->IsDIPEnabled()) {
     gfx::Display display = screen->GetDisplayNearestWindow(view);
     return display.device_scale_factor();
   }
   return 1.0f;
 }
 #endif  // !defined(OS_MACOSX)
 
 }  // namespace ui