Add asADash entry point into SkPathEffect to allow extracting Dash info from PathEffects

BUG=skia:
R=bsalomon@google.com, reed@google.com

Author: egdaniel@google.com

Review URL: https://codereview.chromium.org/212103010

git-svn-id: http://skia.googlecode.com/svn/trunk@14297 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gyp/tests.gypi b/gyp/tests.gypi
index e6c6bb0..f27b144 100644
--- a/gyp/tests.gypi
+++ b/gyp/tests.gypi
@@ -34,6 +34,7 @@
     '../tests/ARGBImageEncoderTest.cpp',
     '../tests/AndroidPaintTest.cpp',
     '../tests/AnnotationTest.cpp',
+    '../tests/AsADashTest.cpp',
     '../tests/AtomicTest.cpp',
     '../tests/BBoxHierarchyTest.cpp',
     '../tests/BitSetTest.cpp',