Revert of Add Gr*Proxy classes (patchset #9 id:160001 of https://codereview.chromium.org/1937553002/ )

Reason for revert:
Seems to be breaking N7 & ANGLE bots

Original issue's description:
> Add Gr*Proxy classes
>
> This isn't wired in anywhere yet.
>
> GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1937553002
>
> Committed: https://skia.googlesource.com/skia/+/de5bf0cfeca908b81a28cc50065f7bc2da3d2fd1

TBR=bsalomon@google.com
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review-Url: https://codereview.chromium.org/1949463002
diff --git a/tests/PrimitiveProcessorTest.cpp b/tests/PrimitiveProcessorTest.cpp
index a82237d..b1157a3 100644
--- a/tests/PrimitiveProcessorTest.cpp
+++ b/tests/PrimitiveProcessorTest.cpp
@@ -104,7 +104,7 @@
 DEF_GPUTEST_FOR_ALL_GL_CONTEXTS(VertexAttributeCount, reporter, ctxInfo) {
     GrContext* context = ctxInfo.fGrContext;
 
-    sk_sp<GrDrawContext> dc(context->newDrawContext(SkBackingFit::kApprox,
+    sk_sp<GrDrawContext> dc(context->newDrawContext(GrContext::kLoose_BackingFit,
                                                     1, 1, kRGBA_8888_GrPixelConfig));
     if (!dc) {
         ERRORF(reporter, "Could not create draw context.");