Add Make[backend] calls for creating GrContexts

Docs-Preview: https://skia.org/?cl=26369
Bug: skia:
Change-Id: I460ee63e466f85b05918479f068a2e5ca2d70550
Reviewed-on: https://skia-review.googlesource.com/26369
Commit-Queue: Greg Daniel <egdaniel@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
diff --git a/bench/GrResourceCacheBench.cpp b/bench/GrResourceCacheBench.cpp
index 9c9ca35..d78af0a 100644
--- a/bench/GrResourceCacheBench.cpp
+++ b/bench/GrResourceCacheBench.cpp
@@ -69,7 +69,7 @@
     }
 
     void onDraw(int loops, SkCanvas* canvas) override {
-        sk_sp<GrContext> context(GrContext::Create(kMock_GrBackend, (GrBackendContext) nullptr));
+        sk_sp<GrContext> context(GrContext::MakeMock(nullptr));
         if (nullptr == context) {
             return;
         }
@@ -115,7 +115,7 @@
     }
 
     void onDelayedSetup() override {
-        fContext.reset(GrContext::Create(kMock_GrBackend, (GrBackendContext) nullptr));
+        fContext = GrContext::MakeMock(nullptr);
         if (!fContext) {
             return;
         }