Revert "Remove all KTX support"

This reverts commit ada12ab0557a1f540e775288e2ce44f64fcd8c7e.

Reason for revert: Google3 needs it:
https://test.corp.google.com/ui#id=OCL:142184832:BASE:142184975:1481839118985:32fde8ef

Original change's description:
> Remove all KTX support
> 
> It is untested and unused.
> 
> Change-Id: I010ff4ad942738f362d42a99af4edbbb1cb0cd71
> Reviewed-on: https://skia-review.googlesource.com/6142
> Commit-Queue: Leon Scroggins <scroggo@google.com>
> Reviewed-by: Mike Klein <mtklein@chromium.org>
> Reviewed-by: Robert Phillips <robertphillips@google.com>
> 

TBR=mtklein@chromium.org,mtklein@google.com,robertphillips@google.com,scroggo@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Change-Id: I1ea2f9487eb2212efbfcc514122792b70c9e8737
Reviewed-on: https://skia-review.googlesource.com/6181
Commit-Queue: Leon Scroggins <scroggo@google.com>
Reviewed-by: Leon Scroggins <scroggo@google.com>
diff --git a/public.bzl b/public.bzl
index 33542ea..5c2e09f 100644
--- a/public.bzl
+++ b/public.bzl
@@ -86,6 +86,8 @@
         "third_party/etc1/*.h",
         "third_party/gif/*.cpp",
         "third_party/gif/*.h",
+        "third_party/ktx/*.cpp",
+        "third_party/ktx/*.h",
     ],
     # Note: PRIVATE_HDRS_INCLUDE_LIST is excluded from BASE_SRCS_ALL here
     # because they are required to appear in srcs for some rules but hdrs for
@@ -383,6 +385,7 @@
     "src/utils",
     "third_party/etc1",
     "third_party/gif",
+    "third_party/ktx",
 ]
 
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