Revert of Use presence of a content key as non-scratch indicator (patchset #5 id:80001 of https://codereview.chromium.org/639873002/)

Reason for revert:
breaking nanobench on ubuntu

Original issue's description:
> Use presence of a content key as non-scratch indicator
>
> BUG=skia:2889
>
> Committed: https://skia.googlesource.com/skia/+/9eefe0851eeaa8ded05b4774ebcb38ed201d5dbf

TBR=robertphillips@google.com
NOTREECHECKS=true
NOTRY=true
BUG=skia:2889

Review URL: https://codereview.chromium.org/642493003

1 files changed, 11 insertions, 8 deletions

diff --git a/include/gpu/GrGpuResource.h b/include/gpu/GrGpuResource.h
index b01f0e9c34..afd9275d47 100644
--- a/include/gpu/GrGpuResource.h
+++ b/include/gpu/GrGpuResource.h
@@ -71,7 +71,7 @@ public:
     }
 
 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 @@ private:
 
     // 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 @@ public:
      */
     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