Hide GrBackendTexture/RenderTarget constructors that take a GrPixelConfig

Make GrGLTexture use the version that takes GrMipMapped.

Bug: skia:6718
Change-Id: Id3e801bcb5e781938e610bdea75bd92498117935
Reviewed-on: https://skia-review.googlesource.com/116221
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
diff --git a/src/gpu/gl/GrGLTexture.cpp b/src/gpu/gl/GrGLTexture.cpp
index 8fe9927..61bce35 100644
--- a/src/gpu/gl/GrGLTexture.cpp
+++ b/src/gpu/gl/GrGLTexture.cpp
@@ -113,7 +113,8 @@
 
 bool GrGLTexture::onStealBackendTexture(GrBackendTexture* backendTexture,
                                         SkImage::BackendTextureReleaseProc* releaseProc) {
-    *backendTexture = GrBackendTexture(width(), height(), config(), fInfo);
+    *backendTexture = GrBackendTexture(this->width(), this->height(),
+                                       this->texturePriv().mipMapped(), fInfo);
     // Set the release proc to a no-op function. GL doesn't require any special cleanup.
     *releaseProc = [](GrBackendTexture){};