Use correct favicon scale factor on Android.

ui/base/layout.cc

Index: ui/base/layout.cc
diff --git a/ui/base/layout.cc b/ui/base/layout.cc
index 367dde33be2c539c9ecc1ac23f5939f18c2f79ce..21f2b116e4bde82366a35e8c5409bc891c4bee2e 100644
--- a/ui/base/layout.cc
+++ b/ui/base/layout.cc
@@ -78,7 +78,17 @@ std::vector<ScaleFactor>& GetSupportedScaleFactorsInternal() {
     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());