Revert of GrResourceCache2 manages scratch texture. (patchset #14 id:260001 of https://codereview.chromium.org/608883003/)

Reason for revert:
Turning bots red:
Nanobench seems to be uniformly failing on Android
(http://108.170.220.21:10117/builders/Perf-Android-Venue8-PowerVR-x86-Release/builds/99/steps/RunNanobench/logs/stdio)

Ubuntu GTX660 32bit is failing in both Debug and Release on GM generation (it appears to be out of memory) (http://108.170.220.120:10117/builders/Test-Ubuntu12-ShuttleA-GTX660-x86-Debug/builds/2457/steps/GenerateGMs/logs/stdio)

Original issue's description:
> GrResourceCache2 manages scratch texture.
>
>
> BUG=skia:
>
> Committed: https://skia.googlesource.com/skia/+/3d398c876440deaab39bbf2a9b881c337e6dc8d4

R=bsalomon@google.com
TBR=bsalomon@google.com
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Author: robertphillips@google.com

Review URL: https://codereview.chromium.org/611383003

1 files changed, 14 insertions, 18 deletions

diff --git a/include/gpu/GrGpuResource.h b/include/gpu/GrGpuResource.h
index 17f34d62b2..61849e7232 100644
--- a/include/gpu/GrGpuResource.h
+++ b/include/gpu/GrGpuResource.h
@@ -49,21 +49,27 @@ public:
     // templated helper classes (e.g. SkAutoTUnref). However, we have different categories of
     // refs (e.g. pending reads). We also don't require thread safety as GrCacheable objects are
     // not intended to cross thread boundaries.
+    // internal_dispose() exists because of GrTexture's reliance on it. It will be removed
+    // soon.
     void ref() const {
-        this->validate();
         ++fRefCnt;
+        // pre-validate once internal_dispose is removed (and therefore 0 ref cnt is not allowed).
+        this->validate();
     }
 
     void unref() const {
         this->validate();
         --fRefCnt;
         if (0 == fRefCnt && 0 == fPendingReads && 0 == fPendingWrites) {
-            SkDELETE(this);
+            this->internal_dispose();
         }
     }
 
-    bool isPurgable() const { return this->reffedOnlyByCache() && !this->internalHasPendingIO(); }
-    bool reffedOnlyByCache() const { return 1 == fRefCnt; }
+    virtual void internal_dispose() const { SkDELETE(this); }
+
+    /** This is exists to service the old mechanism for recycling scratch textures. It will
+        be removed soon. */
+    bool unique() const { return 1 == (fRefCnt + fPendingReads + fPendingWrites); }
 
     void validate() const {
 #ifdef SK_DEBUG
@@ -74,8 +80,9 @@ public:
 #endif
     }
 
+
 protected:
-    GrIORef() : fRefCnt(1), fPendingReads(0), fPendingWrites(0), fIsScratch(kNo_IsScratch) { }
+    GrIORef() : fRefCnt(1), fPendingReads(0), fPendingWrites(0) {}
 
     bool internalHasPendingRead() const { return SkToBool(fPendingReads); }
     bool internalHasPendingWrite() const { return SkToBool(fPendingWrites); }
@@ -91,7 +98,7 @@ private:
         this->validate();
         --fPendingReads;
         if (0 == fRefCnt && 0 == fPendingReads && 0 == fPendingWrites) {
-            SkDELETE(this);
+            this->internal_dispose();
         }
     }
 
@@ -104,7 +111,7 @@ private:
         this->validate();
         --fPendingWrites;
         if (0 == fRefCnt && 0 == fPendingReads && 0 == fPendingWrites) {
-            SkDELETE(this);
+            this->internal_dispose();
         }
     }
 
@@ -115,17 +122,6 @@ private:
 
     // This class is used to manage conversion of refs to pending reads/writes.
     friend class GrGpuResourceRef;
-
-    // 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, IOType> friend class GrPendingIOResource;
 };