Revert of Use presence of a content key as non-scratch indicator

include/gpu/GrGpuResource.h

Index: include/gpu/GrGpuResource.h
diff --git a/include/gpu/GrGpuResource.h b/include/gpu/GrGpuResource.h
index 8800f0afa6439841a4738bad6957e82e91066991..0d523249e9cbd7c933b65d1557ccf02c69140e77 100644
--- a/include/gpu/GrGpuResource.h
+++ b/include/gpu/GrGpuResource.h
@@ -71,7 +71,7 @@
     }
 
 protected:
-    GrIORef() : fRefCnt(1), fPendingReads(0), fPendingWrites(0) { }
+    GrIORef() : fRefCnt(1), fPendingReads(0), fPendingWrites(0), fIsScratch(kNo_IsScratch) { }
 
     bool internalHasPendingRead() const { return SkToBool(fPendingReads); }
     bool internalHasPendingWrite() const { return SkToBool(fPendingWrites); }
@@ -118,7 +118,16 @@
 
     // This class is used to manage conversion of refs to pending reads/writes.
     friend class GrGpuResourceRef;
-    friend class GrResourceCache2; // to check IO ref counts.
+
+    // This is temporary until GrResourceCache is fully replaced by GrResourceCache2.
+    enum IsScratch {
+        kNo_IsScratch,
+        kYes_IsScratch
+    } fIsScratch;
+
+    friend class GrContext; // to set the above field.
+    friend class GrResourceCache; // to check the above field.
+    friend class GrResourceCache2; // to check the above field.
 
     template <typename, GrIOType> friend class GrPendingIOResource;
 };
@@ -181,12 +190,6 @@
      */
     const GrResourceKey& getScratchKey() const { return fScratchKey; }
 
-    /** 
-     * If this resource is currently cached by its contents then this will return
-     * the content key. Otherwise, NULL is returned.
-     */
-    const GrResourceKey* getContentKey() const;
-
     /**
      * Gets an id that is unique for this GrGpuResource object. It is static in that it does
      * not change when the content of the GrGpuResource object changes. This will never return