Implement color filter as GrGLEffect

src/gpu/GrPaint.cpp

Index: src/gpu/GrPaint.cpp
diff --git a/src/gpu/GrPaint.cpp b/src/gpu/GrPaint.cpp
index fec62bbde534542f9966afa9063fdb668584c040..7499cd0ea24d7707a20d9f3c66148ea46fe8a262 100644
--- a/src/gpu/GrPaint.cpp
+++ b/src/gpu/GrPaint.cpp
@@ -56,12 +56,6 @@ bool GrPaint::getOpaqueAndKnownColor(GrColor* solidColor,
 
     // TODO: Share this implementation with GrDrawState
 
-    // Since fColorFilterXfermode is going away soon, we aren't attempting to handle anything but
-    // the default setting.
-    if (SkXfermode::kDst_Mode != fColorFilterXfermode) {
-        return false;
-    }
-
     GrColor coverage = GrColorPackRGBA(fCoverage, fCoverage, fCoverage, fCoverage);
     uint32_t coverageComps = kRGBA_GrColorComponentFlags;
     int count = fCoverageStages.count();