Use correct favicon scale factor on Android.

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 60 matching lines @@
 
 std::vector<ScaleFactor>& GetSupportedScaleFactorsInternal() {
   static std::vector<ScaleFactor>* supported_scale_factors =
       new std::vector<ScaleFactor>();
   if (supported_scale_factors->empty()) {
 #if !defined(OS_IOS)
     // On platforms other than iOS, 100P is always a supported scale factor.
     supported_scale_factors->push_back(SCALE_FACTOR_100P);
 #endif
 
-#if defined(OS_IOS)
+#if defined(OS_ANDROID)
+    const gfx::Display display =
+        gfx::Screen::GetNativeScreen()->GetPrimaryDisplay();
+    const float display_density = display.device_scale_factor();
+    for (int i = NUM_SCALE_FACTORS - 1; i > SCALE_FACTOR_100P; --i) {
+      if (display_density >= kScaleFactorScales[i]) {

[Nico, 2013/01/17 06:31:33]

Is 2.0 high enough for android? Nexus 10 has close to 3x, right? Are 1.4 and 1.8
good fits?

Also, you seem to pick the largest factor <= the display scale factor – isn't it
better to pick the smallest >=?

[aruslan, 2013/01/17 23:01:10]

1.5 and 3.0 are closer matches for 240 (mdpi) and 480 (xxhdpi) dpi with the
baseline of 160 dpi.  I extended the enum and array to match.
Done.
Done.

+        supported_scale_factors->push_back(static_cast<ScaleFactor>(i));
+        break;
+      }
+    }
+#elif defined(OS_IOS)
     gfx::Display display = gfx::Screen::GetNativeScreen()->GetPrimaryDisplay();
     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);
@@ skipping 89 matching lines @@
   gfx::Screen* screen = gfx::Screen::GetScreenFor(view);
   if (screen->IsDIPEnabled()) {
     gfx::Display display = screen->GetDisplayNearestWindow(view);
     return GetScaleFactorFromScale(display.device_scale_factor());
   }
   return ui::SCALE_FACTOR_100P;
 }
 #endif  // !defined(OS_MACOSX)
 
 }  // namespace ui