Creating functions for uploading a mipmapped texture.

src/gpu/SkGr.cpp

Index: src/gpu/SkGr.cpp
diff --git a/src/gpu/SkGr.cpp b/src/gpu/SkGr.cpp
index bb041312450ae278c8ede6bf70dfedc6d02be3ba..d94f4d3768c1ee62b67adb05dd80a897d48a47ec 100644
--- a/src/gpu/SkGr.cpp
+++ b/src/gpu/SkGr.cpp
@@ -646,6 +646,32 @@ GrTexture* GrRefCachedBitmapTexture(GrContext* ctx,
 
     return NULL;
 }
+
+GrTexture* GrMipmapTexture(GrContext* ctx,
+                           const SkBitmap& bitmap,
+                           SkDiscardableFactoryProc fact,
+                           const GrTextureParams* params) {
+    GrTexture* result = bitmap.getTexture();
+    // TODO: What if the bitmap already contains a non-mipmapped texture?
+    if (result) {
+        // TODO: Add stretching. After reading get_stretch(), it appears small
+        // textures can have issues.
+        return SkRef(result);
+    }
+
+    GrSurfaceDesc desc;
+    generate_bitmap_texture_desc(bitmap, &desc);
+
+    auto mipmap = SkMipMap::Build(bitmap, fact);
+    if (mipmap == NULL) {
+        // could not create the mipmap
+        return NULL;
+    } else {
+        return ctx->textureProvider()->createMipmappedTexture(desc, true, *mipmap);
+        // TODO: BitmapInvalidator support
+    }
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 
 // alphatype is ignore for now, but if GrPixelConfig is expanded to encompass