Google3 <functional> has a global "using std::plus"...

src/core/SkXfermode.cpp

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkXfermode.h"
 #include "SkXfermode_proccoeff.h"
 #include "SkColorPriv.h"
@@ skipping 1443 matching lines @@
 
 KERNEL(srcin)    { return s * da; }
 KERNEL(srcout)   { return s * inv(da); }
 KERNEL(srcatop)  { return s*da + d*inv(sa); }
 KERNEL(dstin)    { return srcin  (d,da,s,sa); }
 KERNEL(dstout)   { return srcout (d,da,s,sa); }
 KERNEL(dstatop)  { return srcatop(d,da,s,sa); }
 
 KERNEL(modulate) { return s*d; }
 KERNEL(multiply) { return s*inv(da) + d*inv(sa) + s*d; }
-KERNEL(plus)     { return s + d; }
+KERNEL(plus_)     { return s + d; }
 KERNEL(screen)   { return s + d - s*d; }
 KERNEL(xor_)     { return s*inv(da) + d*inv(sa); }
 
 // Most of the rest apply the same logic to each color channel, and srcover's logic to alpha.
 // (darken and lighten can actually go either way, but they're a little faster this way.)
 template <Sk4f kernel(const Sk4f& s, const Sk4f& sa, const Sk4f& d, const Sk4f& da)>
 static void SK_VECTORCALL rgb_srcover(SkRasterPipeline::Stage* st, size_t x,
                                       Sk4f  r, Sk4f  g, Sk4f  b, Sk4f  a,
                                       Sk4f dr, Sk4f dg, Sk4f db, Sk4f da) {
     r = kernel(r,a,dr,da);
@@ skipping 49 matching lines @@
         case kDstATop_Mode: p->append(rgba<dstatop>); return true;
         case kSrcIn_Mode:   p->append(rgba<srcin>);   return true;
         case kDstIn_Mode:   p->append(rgba<dstin>);   return true;
         case kSrcOut_Mode:  p->append(rgba<srcout>);  return true;
         case kDstOut_Mode:  p->append(rgba<dstout>);  return true;
         case kDstOver_Mode: p->append(rgba<dstover>); return true;
 
         case kClear_Mode:    p->append(rgba<clear>);    return true;
         case kModulate_Mode: p->append(rgba<modulate>); return true;
         case kMultiply_Mode: p->append(rgba<multiply>); return true;
-        case kPlus_Mode:     p->append(rgba<plus>);     return true;
+        case kPlus_Mode:     p->append(rgba<plus_>);    return true;
         case kScreen_Mode:   p->append(rgba<screen>);   return true;
         case kXor_Mode:      p->append(rgba<xor_>);     return true;
 
         case kColorBurn_Mode:  p->append(rgb_srcover<colorburn>);  return true;
         case kColorDodge_Mode: p->append(rgb_srcover<colordodge>); return true;
         case kDarken_Mode:     p->append(rgb_srcover<darken>);     return true;
         case kDifference_Mode: p->append(rgb_srcover<difference>); return true;
         case kExclusion_Mode:  p->append(rgb_srcover<exclusion>);  return true;
         case kHardLight_Mode:  p->append(rgb_srcover<hardlight>);  return true;
         case kLighten_Mode:    p->append(rgb_srcover<lighten>);    return true;
         case kOverlay_Mode:    p->append(rgb_srcover<overlay>);    return true;
         case kSoftLight_Mode:  p->append(rgb_srcover<softlight>);  return true;
 
         // TODO
         case kColor_Mode:       return false;
         case kHue_Mode:         return false;
         case kLuminosity_Mode:  return false;
         case kSaturation_Mode:  return false;
     }
     return false;
 }