Brian requested a new namespace for factories that create fragment processors that combine 2 things with a xfermode.  This way, we can change the implementation of these factories in the future to not use GrComposeEffect if desired.

BUG=skia:4182

Review URL: https://codereview.chromium.org/1306163005
diff --git a/gyp/gpu.gypi b/gyp/gpu.gypi
index 818f2b2..2f49181 100644
--- a/gyp/gpu.gypi
+++ b/gyp/gpu.gypi
@@ -48,6 +48,7 @@
       '<(skia_include_path)/gpu/effects/GrCustomXfermode.h',
       '<(skia_include_path)/gpu/effects/GrExtractAlphaFragmentProcessor.h',
       '<(skia_include_path)/gpu/effects/GrPorterDuffXferProcessor.h',
+      '<(skia_include_path)/gpu/effects/GrXfermodeFragmentProcessor.h',
 
       '<(skia_include_path)/gpu/gl/GrGLConfig.h',
       '<(skia_include_path)/gpu/gl/GrGLExtensions.h',
@@ -289,6 +290,7 @@
       '<(skia_src_path)/gpu/effects/GrTextureDomain.h',
       '<(skia_src_path)/gpu/effects/GrTextureStripAtlas.cpp',
       '<(skia_src_path)/gpu/effects/GrTextureStripAtlas.h',
+      '<(skia_src_path)/gpu/effects/GrXfermodeFragmentProcessor.cpp',
       '<(skia_src_path)/gpu/effects/GrYUVtoRGBEffect.cpp',
       '<(skia_src_path)/gpu/effects/GrYUVtoRGBEffect.h',