Move SkPixelXorXfermode.h to include/client/android

This intended to make clients aware that the SkPixelXorXfermode is Android-specific

This needs to land after the Chromium CL https://codereview.chromium.org/1647953006/ (Add include/client/android to skia .gn & .gypi files)

GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1645093002

Committed: https://skia.googlesource.com/skia/+/aa9cb62901075e9d2858353cb041e5e6d4719614

Review URL: https://codereview.chromium.org/1645093002
diff --git a/gyp/effects.gyp b/gyp/effects.gyp
index fa1bf53..2402ed1 100644
--- a/gyp/effects.gyp
+++ b/gyp/effects.gyp
@@ -20,6 +20,7 @@
       ],
       'include_dirs': [
         '../include/effects',
+        '../include/client/android',
         '../include/private',
         '../src/effects',
         '../src/opts',
@@ -28,6 +29,7 @@
       'direct_dependent_settings': {
         'include_dirs': [
           '../include/effects',
+          '../include/client/android',
         ],
       },
       'sources': [