Attempt to improve lifetime management of SkGlyphCache in Ganesh atlas text code.

src/core/SkDescriptor.h

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #ifndef SkDescriptor_DEFINED
 #define SkDescriptor_DEFINED
@@ skipping 84 matching lines @@
         //       remove the aa < stop test in the loop...
         const uint32_t* aa = (const uint32_t*)this;
         const uint32_t* bb = (const uint32_t*)&other;
         const uint32_t* stop = (const uint32_t*)((const char*)aa + fLength);
         do {
             if (*aa++ != *bb++)
                 return false;
         } while (aa < stop);
         return true;
     }
+    bool operator!=(const SkDescriptor& other) const { return !(*this == other); }
 
     uint32_t getChecksum() const { return fChecksum; }
 
     struct Entry {
         uint32_t fTag;
         uint32_t fLen;
     };
 
 #ifdef SK_DEBUG
     uint32_t getCount() const { return fCount; }
@@ skipping 51 matching lines @@
                         + sizeof(SkDescriptor::Entry) + sizeof(void*)                   // for typeface
                         + 32   // slop for occational small extras
     };
     SkDescriptor*   fDesc;
     uint32_t        fStorage[(kStorageSize + 3) >> 2];
 };
 #define SkAutoDescriptor(...) SK_REQUIRE_LOCAL_VAR(SkAutoDescriptor)
 
 
 #endif