GMs: fail gracefully for null surface

A couple more instances where MakeRenderTarget returns nullptr
due to --preAbandonGpuContext.

BUG=skia5282
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1976163002

Review-Url: https://codereview.chromium.org/1976163002
diff --git a/gm/image_pict.cpp b/gm/image_pict.cpp
index fd7ac2a..9d1dc51 100644
--- a/gm/image_pict.cpp
+++ b/gm/image_pict.cpp
@@ -212,11 +212,13 @@
         , fCtx(SkRef(ctx))
     {
         auto surface(SkSurface::MakeRenderTarget(ctx, SkBudgeted::kNo, info));
-        surface->getCanvas()->clear(0);
-        surface->getCanvas()->translate(-100, -100);
-        surface->getCanvas()->drawPicture(pic);
-        sk_sp<SkImage> image(surface->makeImageSnapshot());
-        fTexture.reset(SkRef(as_IB(image)->peekTexture()));
+        if (surface) {
+            surface->getCanvas()->clear(0);
+            surface->getCanvas()->translate(-100, -100);
+            surface->getCanvas()->drawPicture(pic);
+            sk_sp<SkImage> image(surface->makeImageSnapshot());
+            fTexture.reset(SkRef(as_IB(image)->peekTexture()));
+        }
     }
 protected:
     GrTexture* onGenerateTexture(GrContext* ctx, const SkIRect* subset) override {
@@ -224,6 +226,10 @@
             SkASSERT(ctx == fCtx.get());
         }
 
+        if (!fTexture) {
+            return nullptr;
+        }
+
         if (!subset) {
             return SkRef(fTexture.get());
         }