Make compressedBackendFormat accessible from GrContextThreadSafeProxy

Not having this available on GrContextThreadSafeProxy was an oversight.
This will allow Chrome to correctly prepare the correct type of compressed promise image.

Change-Id: I3002609fef00a130fe409f318ae0f442ef7591d6
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/437016
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
diff --git a/include/gpu/GrContextThreadSafeProxy.h b/include/gpu/GrContextThreadSafeProxy.h
index f645b87..ed0b884 100644
--- a/include/gpu/GrContextThreadSafeProxy.h
+++ b/include/gpu/GrContextThreadSafeProxy.h
@@ -105,6 +105,15 @@
      */
     GrBackendFormat defaultBackendFormat(SkColorType ct, GrRenderable renderable) const;
 
+    /**
+     * Retrieve the GrBackendFormat for a given SkImage::CompressionType. This is
+     * guaranteed to match the backend format used by the following
+     * createCompressedBackendTexture methods that take a CompressionType.
+     *
+     * The caller should check that the returned format is valid.
+     */
+    GrBackendFormat compressedBackendFormat(SkImage::CompressionType c) const;
+
     bool isValid() const { return nullptr != fCaps; }
 
     bool operator==(const GrContextThreadSafeProxy& that) const {
diff --git a/include/gpu/GrDirectContext.h b/include/gpu/GrDirectContext.h
index 532d41e..66703bd 100644
--- a/include/gpu/GrDirectContext.h
+++ b/include/gpu/GrDirectContext.h
@@ -655,6 +655,7 @@
      * Retrieve the GrBackendFormat for a given SkImage::CompressionType. This is
      * guaranteed to match the backend format used by the following
      * createCompressedBackendTexture methods that take a CompressionType.
+     *
      * The caller should check that the returned format is valid.
      */
     using GrRecordingContext::compressedBackendFormat;