Move GrContextPriv methods to their own .cpp file

Centralize these for my sanity. Most will also be parceled out to other contexts.

Change-Id: If0e7e98bcf66c4d8a3391f9b04e643ccc91af4ad
Reviewed-on: https://skia-review.googlesource.com/c/189488
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
diff --git a/src/gpu/GrGpu.h b/src/gpu/GrGpu.h
index ed9be12..917e887 100644
--- a/src/gpu/GrGpu.h
+++ b/src/gpu/GrGpu.h
@@ -317,8 +317,10 @@
         void incNumDraws() { fNumDraws++; }
         void incNumFailedDraws() { ++fNumFailedDraws; }
         void incNumFinishFlushes() { ++fNumFinishFlushes; }
+#if GR_TEST_UTILS
         void dump(SkString*);
         void dumpKeyValuePairs(SkTArray<SkString>* keys, SkTArray<double>* values);
+#endif
         int numDraws() const { return fNumDraws; }
         int numFailedDraws() const { return fNumFailedDraws; }
         int numFinishFlushes() const { return fNumFinishFlushes; }
@@ -333,8 +335,11 @@
         int fNumFailedDraws;
         int fNumFinishFlushes;
 #else
+
+#if GR_TEST_UTILS
         void dump(SkString*) {}
         void dumpKeyValuePairs(SkTArray<SkString>*, SkTArray<double>*) {}
+#endif
         void incRenderTargetBinds() {}
         void incShaderCompilations() {}
         void incTextureCreates() {}