Make GrPaint have a variable sized array of color and coverage stages rather than a fixed size.

src/effects/SkXfermodeImageFilter.cpp

 /*
  * Copyright 2013 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 "SkXfermodeImageFilter.h"
 #include "SkCanvas.h"
 #include "SkColorPriv.h"
@@ skipping 101 matching lines @@
     SkXfermode::Coeff sm, dm;
     if (!SkXfermode::AsNewEffectOrCoeff(fMode, context, &xferEffect, &sm, &dm, backgroundTex)) {
         return false;
     }
 
     SkMatrix foregroundMatrix = GrEffect::MakeDivByTextureWHMatrix(foregroundTex);
     foregroundMatrix.preTranslate(SkIntToScalar(backgroundOffset.fX-foregroundOffset.fX),
                                   SkIntToScalar(backgroundOffset.fY-foregroundOffset.fY));
 
 
-    GrPaint paint;
     SkRect srcRect;
     src.getBounds(&srcRect);
     if (NULL != xferEffect) {
-        paint.colorStage(0)->setEffect(
-            GrSimpleTextureEffect::Create(foregroundTex, foregroundMatrix))->unref();
-        paint.colorStage(1)->setEffect(xferEffect)->unref();
+        GrPaint paint;
+        paint.addColorTextureEffect(foregroundTex, foregroundMatrix);
+        paint.addColorEffect(xferEffect)->unref();
         context->drawRect(paint, srcRect);
     } else {
+        GrPaint backgroundPaint;
         SkMatrix backgroundMatrix = GrEffect::MakeDivByTextureWHMatrix(backgroundTex);
-        paint.colorStage(0)->setEffect(
-            GrSimpleTextureEffect::Create(backgroundTex, backgroundMatrix))->unref();
-        context->drawRect(paint, srcRect);
-        paint.setBlendFunc(sk_blend_to_grblend(sm), sk_blend_to_grblend(dm));
-        paint.colorStage(0)->setEffect(
-            GrSimpleTextureEffect::Create(foregroundTex, foregroundMatrix))->unref();
-        context->drawRect(paint, srcRect);
+        backgroundPaint.addColorTextureEffect(backgroundTex, backgroundMatrix);
+        context->drawRect(backgroundPaint, srcRect);
+
+        GrPaint foregroundPaint;
+        foregroundPaint.setBlendFunc(sk_blend_to_grblend(sm), sk_blend_to_grblend(dm));
+        foregroundPaint.addColorTextureEffect(foregroundTex, foregroundMatrix);
+        context->drawRect(foregroundPaint, srcRect);
     }
     offset->fX += backgroundOffset.fX;
     offset->fY += backgroundOffset.fY;
     return SkImageFilterUtils::WrapTexture(dst, src.width(), src.height(), result);
 }
 
 #endif