Revert of Modifying TextBlobCacheTest to use SkRandomScalerContext

src/gpu/GrBatchAtlas.cpp

Index: src/gpu/GrBatchAtlas.cpp
diff --git a/src/gpu/GrBatchAtlas.cpp b/src/gpu/GrBatchAtlas.cpp
index 59f2428cd971b15f285df5c2389c4bb7e94b73de..c11c32b38db334072e821b4007e0e4687581f24b 100644
--- a/src/gpu/GrBatchAtlas.cpp
+++ b/src/gpu/GrBatchAtlas.cpp
@@ -42,10 +42,7 @@
     // across atlas spills)
     int index() const { return fIndex; }
     int genID() const { return fGenID; }
-    GrBatchAtlas::AtlasID id() {
-        SkASSERT(GrBatchAtlas::kInvalidAtlasID != fID);
-        return fID;
-    }
+    GrBatchAtlas::AtlasID id() { return fID; }
 
     GrTexture* texture() const { return fTexture; }