Include the SkTSort header only where it is used.

Change-Id: If51be35205b40c4a22979a4b49b031126af1dde7
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/302500
Commit-Queue: John Stiles <johnstiles@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
diff --git a/tools/viewer/Viewer.cpp b/tools/viewer/Viewer.cpp
index 603f2b7..a6a34d6 100644
--- a/tools/viewer/Viewer.cpp
+++ b/tools/viewer/Viewer.cpp
@@ -19,6 +19,7 @@
 #include "src/core/SkMD5.h"
 #include "src/core/SkOSFile.h"
 #include "src/core/SkScan.h"
+#include "src/core/SkTSort.h"
 #include "src/core/SkTaskGroup.h"
 #include "src/core/SkTextBlobPriv.h"
 #include "src/gpu/GrContextPriv.h"