Enable subpixel positioning for internal display with dsf larger than 1.0

ui/gfx/font_render_params_linux_unittest.cc

 // Copyright 2014 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/gfx/font_render_params.h"
 
 #include "base/files/file_path.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/logging.h"
 #include "base/macros.h"
@@ skipping 255 matching lines @@
   // more information.
   FontRenderParams params = GetFontRenderParams(
       FontRenderParamsQuery(false), NULL);
   EXPECT_FALSE(params.antialiasing);
   EXPECT_EQ(FontRenderParams::HINTING_FULL, params.hinting);
   EXPECT_EQ(FontRenderParams::SUBPIXEL_RENDERING_NONE,
             params.subpixel_rendering);
   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.
   FontRenderParams system_params;
   system_params.subpixel_rendering = FontRenderParams::SUBPIXEL_RENDERING_RGB;
   test_font_delegate_.set_params(system_params);
 
   // Load a Fontconfig config that enables antialiasing but doesn't say anything
   // about subpixel rendering.
   ASSERT_TRUE(LoadSystemFont("arial.ttf"));
@@ skipping 66 matching lines @@
   EXPECT_EQ("Verdana", suggested_family);
 
   query.families.clear();
   query.families.push_back("Arial");
   suggested_family.clear();
   GetFontRenderParams(query, &suggested_family);
   EXPECT_EQ("Verdana", suggested_family);
 }
 
 }  // namespace gfx