Run CanvasState test across a library boundary.

gyp/canvas_state_lib.gyp

+# Building test for running CanvasState
+
+# HOW TO USE:
+# This target is not included in normal Skia builds. In order to build it,
+# you need to run gyp_skia on this file. This target also requires the
+# variable skia_pic to be used during building:
+#
+# GYP_DEFINES=skia_pic=1 ./gyp_skia gyp/canvas_state_lib.gyp
+# ninja -C out/Debug canvas_state_lib
+#
+# This will create the shared library libcanvas_state_lib.so. That can
+# be passed to tests to test passing an SkCanvas between versions of
+# Skia. See tests/CanvasStateTest.cpp for more info.
+{
+  'targets' : [
+    {
+      'target_name' : 'canvas_state_lib',
+      'type' : 'shared_library',
+      # FIXME: Is there a way to ensure that -fPIC was used for skia_lib?
+      'dependencies' : [ 'skia_lib.gyp:skia_lib'],
+      'sources' : [
+        '../tests/CanvasStateHelpers.cpp',
+      ],
+      'cflags' : [
+        '-fPIC',
+      ],
+    },
+    {
+        # Dummy 'most' target, since gyp_skia sets 'most' to be the default.
+        'target_name' : 'most',
+        'type'        : 'none',
+        'dependencies' : [
+          'canvas_state_lib',
+        ],
+    }
+  ],
+}