remove prepForSampling from GrSurfaceContext::writePixels.

We believe with advent of  GrBackendSurfaceMutableState that this is
only needed for inline atlas uploads. Those call GrGpu directly.

Bug: 1191058
Change-Id: Iad851ebc9f5b7df21d16064a84caa9575da98634
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/393082
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
diff --git a/src/gpu/GrDrawingManager.cpp b/src/gpu/GrDrawingManager.cpp
index 8aec8f3..6d822cd 100644
--- a/src/gpu/GrDrawingManager.cpp
+++ b/src/gpu/GrDrawingManager.cpp
@@ -820,8 +820,7 @@
                                           GrColorType srcColorType,
                                           GrColorType dstColorType,
                                           const GrMipLevel levels[],
-                                          int levelCount,
-                                          bool prepForSampling) {
+                                          int levelCount) {
     SkDEBUGCODE(this->validate());
     SkASSERT(fContext);
 
@@ -843,8 +842,7 @@
                                                                   srcColorType,
                                                                   dstColorType,
                                                                   levels,
-                                                                  levelCount,
-                                                                  prepForSampling));
+                                                                  levelCount));
     if (!task) {
         return false;
     }