Enable subpixel positioning for internal display with dsf larger than 1.0

ui/gfx/font_render_params_linux_unittest.cc

Index: ui/gfx/font_render_params_linux_unittest.cc
diff --git a/ui/gfx/font_render_params_linux_unittest.cc b/ui/gfx/font_render_params_linux_unittest.cc
index f89c3967067535c521260ccac86a03eff8b8a5dc..aa9053ef3d7ade13a32e625d9ca89bc1ea4b330e 100644
--- a/ui/gfx/font_render_params_linux_unittest.cc
+++ b/ui/gfx/font_render_params_linux_unittest.cc
@@ -273,6 +273,25 @@ TEST_F(FontRenderParamsTest, ForceFullHintingWhenAntialiasingIsDisabled) {
   EXPECT_FALSE(params.subpixel_positioning);
 }
 
+TEST_F(FontRenderParamsTest, ForceSubpixelPositioning) {

[Daniel Erat, 2014/08/19 22:32:25]

this should only be for OS_CHROMEOS, right?

[oshima, 2014/08/20 01:41:13]

Done.

+  // Load a config that disables antialiasing and hinting while requesting
+  // subpixel rendering.
+  ASSERT_TRUE(LoadSystemFont("arial.ttf"));
+  ASSERT_TRUE(LoadConfigDataIntoFontconfig(
+      temp_dir_.path(),
+      std::string(kFontconfigFileHeader) + kFontconfigMatchHeader +
+          CreateFontconfigEditStanza("rgba", "const", "rgb") +

[Daniel Erat, 2014/08/19 22:32:25]

do you need this? it seems to be outside the scope of the code that you're
testing, and you aren't checking the subpixel_rendering field either

[oshima, 2014/08/20 01:41:13]

Done.

+          kFontconfigMatchFooter + kFontconfigFileFooter));
+  SetDeviceScaleFactorForInternalDisplay(1.25f);
+  // Full hinting should be forced. See the comment in GetFontRenderParams() for
+  // more information.

[Daniel Erat, 2014/08/19 22:32:25]

this comment seems wrong

[oshima, 2014/08/20 01:41:13]

Done.

+  FontRenderParams params =
+      GetFontRenderParams(FontRenderParamsQuery(false), NULL);
+  EXPECT_TRUE(params.antialiasing);
+  EXPECT_TRUE(params.subpixel_positioning);
+  SetDeviceScaleFactorForInternalDisplay(1.0f);

[Daniel Erat, 2014/08/19 22:32:25]

what's the reason for this? note that the cache gets reset between tests.

you could also try sending a different query after setting it to 1.0 and
checking that subpixel positioning isn't enabled.

[oshima, 2014/08/20 01:41:13]

This is necessary so that other test does not use this value.
Setting it back does not change the value of params.subpixel_positioning as it
cashes the result.

And we never set it back, so I don't think we need to test that scenario.

+}
+
 TEST_F(FontRenderParamsTest, OnlySetConfiguredValues) {
   // Configure the LinuxFontDelegate (which queries GtkSettings on desktop
   // Linux) to request subpixel rendering.