Rename GrTextureAccess to GrProcessor::TextureSampler.

Renames vars and methods that used the work "access" to refer to this type.

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4931

Change-Id: Ibcf488fbd445c5119fc13d190544cd98981bdbee
Reviewed-on: https://skia-review.googlesource.com/4931
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
diff --git a/src/gpu/GrXferProcessor.cpp b/src/gpu/GrXferProcessor.cpp
index 76e0ba0..2769c18 100644
--- a/src/gpu/GrXferProcessor.cpp
+++ b/src/gpu/GrXferProcessor.cpp
@@ -26,7 +26,7 @@
         SkASSERT(willReadDstColor);
         fDstTexture.reset(dstTexture->texture());
         fDstTextureOffset = dstTexture->offset();
-        this->addTextureAccess(&fDstTexture);
+        this->addTextureSampler(&fDstTexture);
         this->setWillReadFragmentPosition();
     }
 }