Move implementation of SkFilterShader into its source file.

Since SkFilterShader has its own header file, makes more sense to have a
separate source file to implement it rather than placing it in a "random"
SkColorFilter.cpp file.

R=robertphillips@google.com

Review URL: https://codereview.chromium.org/19305004

git-svn-id: http://skia.googlecode.com/svn/trunk@10101 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gyp/core.gypi b/gyp/core.gypi
index e87c0f4..deb2c50 100644
--- a/gyp/core.gypi
+++ b/gyp/core.gypi
@@ -80,6 +80,7 @@
         '<(skia_src_path)/core/SkFP.h',
         '<(skia_src_path)/core/SkFilterProc.cpp',
         '<(skia_src_path)/core/SkFilterProc.h',
+        '<(skia_src_path)/core/SkFilterShader.cpp',
         '<(skia_src_path)/core/SkFlattenable.cpp',
         '<(skia_src_path)/core/SkFlattenableBuffers.cpp',
         '<(skia_src_path)/core/SkFloat.cpp',