Plumbing mipmaps to the point of creation.

When creating a DeferredTextureImage we may create mipmaps.
Those mipmaps need to then be passed along for when the texture is
actually created.

R=bsalomon@google.com
BUG=578304
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2031273002

Review-Url: https://codereview.chromium.org/2031273002
diff --git a/src/image/SkImage.cpp b/src/image/SkImage.cpp
index 8bf1f24..1c1b311 100644
--- a/src/image/SkImage.cpp
+++ b/src/image/SkImage.cpp
@@ -499,3 +499,8 @@
     return MakeFromDeferredTextureImageData(ctx, data, budgeted).release();
 }
 #endif
+
+sk_sp<SkImage> MakeTextureFromMipMap(GrContext*, const SkImageInfo&, const GrMipLevel* texels,
+                                     int mipLevelCount, SkBudgeted) {
+    return nullptr;
+}