Create a GrGpu::createBackendTexture choke point

This also makes createBackendTexture take SkPixmaps (instead of a raw pixels pointer)

Change-Id: I5d8a5a58fa7b15862fbf46a3c232cb6ea7f58976
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/243158
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
diff --git a/src/gpu/GrContextPriv.cpp b/src/gpu/GrContextPriv.cpp
index 511639a..db64798 100644
--- a/src/gpu/GrContextPriv.cpp
+++ b/src/gpu/GrContextPriv.cpp
@@ -393,6 +393,5 @@
     // TODO: propagate the array of pixmaps interface to GrGpu
     return gpu->createBackendTexture(baseWidth, baseHeight, backendFormat,
                                      GrMipMapped::kNo, // TODO: use real mipmap setting here
-                                     renderable, srcData[0].addr(), srcData[0].rowBytes(),
-                                     nullptr, isProtected);
+                                     renderable, srcData, numLevels, nullptr, isProtected);
 }