Remove SkFallbackAlloc and SkFixedAlloc.

CQ_INCLUDE_TRYBOTS=skia.primary:Test-Ubuntu-Clang-GCE-CPU-AVX2-x86_64-Debug-ASAN;skia.primary:Test-Ubuntu-Clang-GCE-CPU-AVX2-x86_64-Debug-MSAN

TBR=reed@google.com

Change-Id: I1000dc9ed8ad65b249798759d9af99f47fc237d2
Reviewed-on: https://skia-review.googlesource.com/6809
Reviewed-by: Herb Derby <herb@google.com>
Commit-Queue: Herb Derby <herb@google.com>
diff --git a/src/core/SkColorShader.h b/src/core/SkColorShader.h
index 19c106d..3f00317 100644
--- a/src/core/SkColorShader.h
+++ b/src/core/SkColorShader.h
@@ -65,7 +65,7 @@
         *lum = fColor;
         return true;
     }
-    bool onAppendStages(SkRasterPipeline*, SkColorSpace*, SkFallbackAlloc*,
+    bool onAppendStages(SkRasterPipeline*, SkColorSpace*, SkArenaAlloc*,
                         const SkMatrix& ctm, const SkPaint&) const override;
 
 private:
@@ -121,7 +121,7 @@
         *lum = fCachedByteColor;
         return true;
     }
-    bool onAppendStages(SkRasterPipeline*, SkColorSpace*, SkFallbackAlloc*,
+    bool onAppendStages(SkRasterPipeline*, SkColorSpace*, SkArenaAlloc*,
                         const SkMatrix& ctm, const SkPaint&) const override;
 
 private: