Update GrPaint APIs to reflect lack of multiple color processors.

Change-Id: Ic7799b3c5f4294cba9ff72f8c11a2ad285ab189f
Bug: skia:10217
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/304738
Commit-Queue: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
diff --git a/samplecode/SampleCCPRGeometry.cpp b/samplecode/SampleCCPRGeometry.cpp
index d87c6a9..0aa8100 100644
--- a/samplecode/SampleCCPRGeometry.cpp
+++ b/samplecode/SampleCCPRGeometry.cpp
@@ -217,7 +217,7 @@
 
         // Visualize coverage count in main canvas.
         GrPaint paint;
-        paint.addColorFragmentProcessor(VisualizeCoverageCountFP::Make(
+        paint.setColorFragmentProcessor(VisualizeCoverageCountFP::Make(
                 GrTextureEffect::Make(ccbuff->readSurfaceView(), ccbuff->colorInfo().alphaType())));
         paint.setPorterDuffXPFactory(SkBlendMode::kSrcOver);
         rtc->drawRect(nullptr, std::move(paint), GrAA::kNo, SkMatrix::I(),