Avoid DCHECK on 3x scaled screens.

ui/base/resource/resource_bundle.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/resource/resource_bundle.h"
 
 #include <limits>
 #include <vector>
 
 #include "base/big_endian.h"
@@ skipping 588 matching lines @@
 #endif
 #if defined(OS_ANDROID)
   const gfx::Display display =
       gfx::Screen::GetNativeScreen()->GetPrimaryDisplay();
   const float display_density = display.device_scale_factor();
   const ScaleFactor closest = FindClosestScaleFactorUnsafe(display_density);
   if (closest != SCALE_FACTOR_100P)
     supported_scale_factors.push_back(closest);
 #elif defined(OS_IOS)
     gfx::Display display = gfx::Screen::GetNativeScreen()->GetPrimaryDisplay();
-  if (display.device_scale_factor() > 1.0) {
+  if (display.device_scale_factor() > 2.0) {
+    DCHECK_EQ(3.0, display.device_scale_factor());
+    // TODO(lliabraa): Add 3x images instead of using 2x on 3x screens.
+    // crbug.com/413300
+    supported_scale_factors.push_back(SCALE_FACTOR_200P);
+  } else if (display.device_scale_factor() > 1.0) {
     DCHECK_EQ(2.0, display.device_scale_factor());
     supported_scale_factors.push_back(SCALE_FACTOR_200P);
   } else {
     supported_scale_factors.push_back(SCALE_FACTOR_100P);
   }
 #elif defined(OS_MACOSX)
   if (base::mac::IsOSLionOrLater())
     supported_scale_factors.push_back(SCALE_FACTOR_200P);
 #elif defined(OS_CHROMEOS)
   // TODO(oshima): Include 200P only if the device support 200P
@@ skipping 231 matching lines @@
 // static
 bool ResourceBundle::DecodePNG(const unsigned char* buf,
                                size_t size,
                                SkBitmap* bitmap,
                                bool* fell_back_to_1x) {
   *fell_back_to_1x = PNGContainsFallbackMarker(buf, size);
   return gfx::PNGCodec::Decode(buf, size, bitmap);
 }
 
 }  // namespace ui