More cleanup around GrContext, textures, and SkGr.cpp

Review URL: https://codereview.chromium.org/880983008
diff --git a/src/gpu/GrTexture.cpp b/src/gpu/GrTexture.cpp
index 6bd4586..4b43fc8 100644
--- a/src/gpu/GrTexture.cpp
+++ b/src/gpu/GrTexture.cpp
@@ -87,7 +87,7 @@
     : INHERITED(gpu, lifeCycle, desc)
     , fMipMapsStatus(kNotAllocated_MipMapsStatus) {
 
-    if (kWrapped_LifeCycle != lifeCycle) {
+    if (kWrapped_LifeCycle != lifeCycle && !GrPixelConfigIsCompressed(desc.fConfig)) {
         GrScratchKey key;
         GrTexturePriv::ComputeScratchKey(desc, &key);
         this->setScratchKey(key);