Don't flush on read/write pixels unless necessary

include/gpu/GrGpuResource.h

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrGpuResource_DEFINED
 #define GrGpuResource_DEFINED
 
@@ skipping 62 matching lines @@
 
     void validate() const {
 #ifdef SK_DEBUG
         SkASSERT(fRefCnt >= 0);
         SkASSERT(fPendingReads >= 0);
         SkASSERT(fPendingWrites >= 0);
         SkASSERT(fRefCnt + fPendingReads + fPendingWrites > 0);
 #endif
     }
 
+
 protected:
     GrIORef() : fRefCnt(1), fPendingReads(0), fPendingWrites(0) {}
 
+    bool internalHasPendingRead() const { return SkToBool(fPendingReads); }
+    bool internalHasPendingWrite() const { return SkToBool(fPendingWrites); }
+    bool internalHasPendingIO() const { return SkToBool(fPendingWrites | fPendingReads); }
+
 private:
     void addPendingRead() const {
         this->validate();
         ++fPendingReads;
     }
 
     void completedRead() const {
         this->validate();
         --fPendingReads;
         if (0 == fRefCnt && 0 == fPendingReads && 0 == fPendingWrites) {
@@ skipping 149 matching lines @@
 
     GrResourceCacheEntry*   fCacheEntry;  // NULL if not in cache
     const uint32_t          fUniqueID;
 
     GrResourceKey           fScratchKey;
 
     typedef GrIORef INHERITED;
 };
 
 #endif