Downgrade GpuGMs to only receiving a GrRecordingContext

Most of this CL is just noise (i.e., all the header changes) due to the
signature change. The 'discard' GM has some substantive changes but
that's about it.

Change-Id: I72011a442c149b5db93cf8decade6779be4f63d8
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/296704
Reviewed-by: Adlai Holler <adlai@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
diff --git a/gm/flippity.cpp b/gm/flippity.cpp
index 18ea1ba..b2a517e 100644
--- a/gm/flippity.cpp
+++ b/gm/flippity.cpp
@@ -25,6 +25,7 @@
 #include "include/core/SkTypes.h"
 #include "include/gpu/GrContext.h"
 #include "include/gpu/GrTypes.h"
+#include "include/private/GrRecordingContext.h"
 #include "include/private/SkTArray.h"
 #include "src/gpu/GrContextPriv.h"
 #include "src/image/SkImage_Base.h"
@@ -273,7 +274,7 @@
         fReferenceImages[0] = fReferenceImages[1] = nullptr;
     }
 
-    void onDraw(GrContext*, GrRenderTargetContext*, SkCanvas* canvas) override {
+    void onDraw(GrRecordingContext*, GrRenderTargetContext*, SkCanvas* canvas) override {
         SkASSERT(fReferenceImages[0] && fReferenceImages[1]);
 
         canvas->save();