Move SkGLContext and some GrGLInterface implementations to skgputest module

BUG=skia:
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Committed: https://skia.googlesource.com/skia/+/fe3456cb006110d045b26ff3f8681b893a757b58

Review URL: https://codereview.chromium.org/1815823002
diff --git a/dm/DM.cpp b/dm/DM.cpp
index d93cd29..79b9e8d 100644
--- a/dm/DM.cpp
+++ b/dm/DM.cpp
@@ -70,6 +70,8 @@
 DEFINE_bool(simpleCodec, false, "Only decode images to native scale");
 
 using namespace DM;
+using sk_gpu_test::GrContextFactory;
+using sk_gpu_test::GLContext;
 
 /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
 
@@ -1416,7 +1418,7 @@
 namespace skiatest {
 namespace {
 typedef void(*TestWithGrContext)(skiatest::Reporter*, GrContext*);
-typedef void(*TestWithGrContextAndGLContext)(skiatest::Reporter*, GrContext*, SkGLContext*);
+typedef void(*TestWithGrContextAndGLContext)(skiatest::Reporter*, GrContext*, GLContext*);
 #if SK_SUPPORT_GPU
 template<typename T>
 void call_test(T test, skiatest::Reporter* reporter, const GrContextFactory::ContextInfo& context);