Enable more tests in GN build.

skia/BUILD.gn

Index: skia/BUILD.gn
diff --git a/skia/BUILD.gn b/skia/BUILD.gn
index b626d3ed155d0322f3c9da1c3529a7d7fecf54d5..65a4131d9b9b458fb3627a03599cf6fab1d544d1 100644
--- a/skia/BUILD.gn
+++ b/skia/BUILD.gn
@@ -248,14 +248,6 @@ component("skia") {
     "ext/benchmarking_canvas.cc",
     "ext/benchmarking_canvas.h",
     "ext/bitmap_platform_device.h",
-    "ext/bitmap_platform_device_cairo.cc",
-    "ext/bitmap_platform_device_cairo.h",
-    "ext/bitmap_platform_device_mac.cc",
-    "ext/bitmap_platform_device_mac.h",
-    #"ext/bitmap_platform_device_skia.cc",
-    #"ext/bitmap_platform_device_skia.h",
-    "ext/bitmap_platform_device_win.cc",
-    "ext/bitmap_platform_device_win.h",
     "ext/convolver.cc",
     "ext/convolver.h",
     "ext/event_tracer_impl.cc",
@@ -469,11 +461,27 @@ component("skia") {
     ]
   }
 
-  if (!use_cairo) {
-    sources -= [
+  # Select the right BitmapPlatformDevice.
+  if (is_win) {
+    sources += [
+      "ext/bitmap_platform_device_win.cc",
+      "ext/bitmap_platform_device_win.h",
+    ]
+  } else if (is_mac) {
+    sources += [ 
+      "ext/bitmap_platform_device_mac.cc",
+      "ext/bitmap_platform_device_mac.h",
+    ]
+  } else if (use_cairo) {
+    sources += [
       "ext/bitmap_platform_device_cairo.cc",
       "ext/bitmap_platform_device_cairo.h",
     ]
+  } else {
+    sources += [
+      "ext/bitmap_platform_device_skia.cc",
+      "ext/bitmap_platform_device_skia.h",
+    ]
   }
 
   if (is_clang) {