Fix scrollbar buttons at hidpi when enable-use-zoom-for-dsf is on.

third_party/WebKit/Source/platform/BUILD.gn

 # 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.
 
 import("//build/config/ui.gni")
 import("//testing/test.gni")
 import("//third_party/WebKit/Source/build/scripts/scripts.gni")
 import("//third_party/WebKit/Source/config.gni")
 import("//third_party/WebKit/Source/platform/platform.gni")
 import("//third_party/WebKit/Source/platform/platform_generated.gni")
@@ skipping 508 matching lines @@
 
   if (is_win) {
     sources += [ "text/LocaleWinTest.cpp" ]
   } else if (is_mac) {
     sources += [ "text/LocaleMacTest.cpp" ]
   } else if (is_posix) {
     sources += [ "text/LocaleICUTest.cpp" ]
   }
 
   if (!is_mac) {
-    sources += [ "scroll/ScrollAnimatorTest.cpp" ]
+    sources += [
+      "scroll/ScrollAnimatorTest.cpp",
+      "scroll/ScrollbarThemeAuraTest.cpp",

[jbroman, 2016/05/11 21:24:08]

The condition for this should probably match that of ScrollbarThemeAura.cpp.
Suggest:

if (use_default_render_theme) {
  sources += [ "scroll/ScrollbarThemeAuraTest.cpp" ]
}

(use_default_render_theme = use_aura && !is_android, for context)

[Bret, 2016/05/12 00:18:12]

Done.

+    ]
   }
 
   sources += [ "testing/RunAllTests.cpp" ]
 
   configs += [
     "//third_party/WebKit/Source/wtf:wtf_config",
     "//third_party/WebKit/Source:config",
   ]
 
   deps = [
@@ skipping 59 matching lines @@
 }
 
 if (current_cpu == "x86" || current_cpu == "x64") {
   source_set("blink_x86_sse") {
     sources = blink_platform_sse_files
     deps = [
       ":blink_common",
     ]
   }
 }