skia: Add 'skia_unittests' test suite for this directory.

skia/BUILD.gn

Index: skia/BUILD.gn
diff --git a/skia/BUILD.gn b/skia/BUILD.gn
index 8d23c068d17d1de7c862f3bef720d1f93486a933..568413d639004551a13e9eeee6c94d9e8095d0a1 100644
--- a/skia/BUILD.gn
+++ b/skia/BUILD.gn
@@ -709,3 +709,36 @@ source_set("skia_opts") {
 
   visibility = [ ":skia" ]
 }
+
+test("skia_unittests") {
+  sources = [
+    "ext/analysis_canvas_unittest.cc",
+    "ext/bitmap_platform_device_mac_unittest.cc",
+    "ext/convolver_unittest.cc",
+    "ext/image_operations_unittest.cc",
+    "ext/pixel_ref_utils_unittest.cc",
+    "ext/platform_canvas_unittest.cc",
+    "ext/recursive_gaussian_convolution_unittest.cc",
+    "ext/refptr_unittest.cc",
+    "ext/skia_utils_ios_unittest.mm",
+    "ext/skia_utils_mac_unittest.mm",
+    "ext/vector_canvas_unittest.cc",
+  ]
+
+  if (!is_win) {
+    sources -= [ "ext/vector_canvas_unittest.cc" ]
+  }
+
+  if (!is_win && !is_mac) {
+    sources -= [ "ext/platform_canvas_unittest.cc" ]
+  }
+
+  deps = [
+    ":skia",
+    "//base",
+    "//base/test:run_all_unittests",
+    "//testing/gtest",
+    "//ui/gfx",
+    "//ui/gfx/geometry",
+  ]
+}