GrConvertPixels takes pixmaps

Add GrCPixmap, a GrPixmap but with const void* instead of void*. Share
impl via template base class GrPixmapBase.

Change-Id: I7dfdf24a73c1bc8557ff7b90f93a9399da2f3f75
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/350022
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
diff --git a/tools/gpu/ProxyUtils.h b/tools/gpu/ProxyUtils.h
index 7ce0122..c4db536 100644
--- a/tools/gpu/ProxyUtils.h
+++ b/tools/gpu/ProxyUtils.h
@@ -15,7 +15,7 @@
 
 class GrDirectContext;
 class GrProgramInfo;
-class GrPixmap;
+class GrCPixmap;
 
 namespace sk_gpu_test {
 
@@ -26,7 +26,7 @@
 GrSurfaceProxyView MakeTextureProxyViewFromData(GrDirectContext*,
                                                 GrRenderable,
                                                 GrSurfaceOrigin,
-                                                GrPixmap pixmap);
+                                                GrCPixmap pixmap);
 
 GrProgramInfo* CreateProgramInfo(const GrCaps*,
                                  SkArenaAlloc*,