Revert of Make GrScratchKey memory buffer correct size on copy

include/gpu/GrResourceKey.h

Index: include/gpu/GrResourceKey.h
diff --git a/include/gpu/GrResourceKey.h b/include/gpu/GrResourceKey.h
index 43c6ff1770653954321cb01c643b005a901cf0a2..f662ed5511e36aa29ce3a0ac1ad8bc6d0a723d61 100644
--- a/include/gpu/GrResourceKey.h
+++ b/include/gpu/GrResourceKey.h
@@ -46,9 +46,9 @@
     const uint32_t* data() const { return &fKey[kMetaDataCnt]; }
 
     GrScratchKey& operator=(const GrScratchKey& that) {
-        size_t bytes = that.size();
-        fKey.reset(SkToInt(bytes / sizeof(uint32_t)));
-        memcpy(fKey.get(), that.fKey.get(), bytes);
+        size_t size = that.size();
+        fKey.reset(SkToInt(size));
+        memcpy(fKey.get(), that.fKey.get(), size);
         return *this;
     }