Update existing TestCreate methods to honor the inputFP in the TestData.

This can be leveraged to build chains of test FPs in a controlled way.
At present, `inputFP` it is never set to anything other than null; as
such, all calls to TestCreate continue to set a null inputFP
(exactly as they do already).

Change-Id: I0d74f37a076ca338e44ff734816299beb1667c26
Bug: skia:10384
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/302668
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
diff --git a/src/gpu/GrProcessorUnitTest.h b/src/gpu/GrProcessorUnitTest.h
index 23fbb4a..731e1ed 100644
--- a/src/gpu/GrProcessorUnitTest.h
+++ b/src/gpu/GrProcessorUnitTest.h
@@ -53,7 +53,9 @@
 public:
     using ViewInfo = std::tuple<GrSurfaceProxyView, GrColorType, SkAlphaType>;
 
-    GrProcessorTestData(SkRandom*, GrRecordingContext*, int numViews, const ViewInfo views[]);
+    GrProcessorTestData(SkRandom* random, GrRecordingContext* context,
+                        int numViews, const ViewInfo views[],
+                        std::unique_ptr<GrFragmentProcessor> inputFP = nullptr);
     GrProcessorTestData(const GrProcessorTestData&) = delete;
     ~GrProcessorTestData();
 
@@ -61,6 +63,7 @@
     GrProxyProvider* proxyProvider();
     const GrCaps* caps();
     SkArenaAlloc* allocator() { return fArena.get(); }
+    std::unique_ptr<GrFragmentProcessor> inputFP();
 
     ViewInfo randomView();
     ViewInfo randomAlphaOnlyView();