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

src/core/SkGlyphCache.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 SkGlyphCache_DEFINED
 #define SkGlyphCache_DEFINED
 
 #include "SkBitmap.h"
@@ skipping 259 matching lines @@
     // used to track (approx) how much ram is tied-up in this cache
     size_t                 fMemoryUsed;
 
     AuxProcRec*            fAuxProcList;
 };
 
 class SkAutoGlyphCache : public std::unique_ptr<SkGlyphCache, SkGlyphCache::AttachCacheFunctor> {
 public:
     /** deprecated: use get() */
     SkGlyphCache* getCache() const { return this->get(); }
-
+    SkAutoGlyphCache() {}
     SkAutoGlyphCache(SkGlyphCache* cache) : INHERITED(cache) {}
     SkAutoGlyphCache(SkTypeface* typeface, const SkScalerContextEffects& effects,
                      const SkDescriptor* desc)
         : INHERITED(SkGlyphCache::DetachCache(typeface, effects, desc))
     {}
     /** deprecated: always enables fake gamma */
     SkAutoGlyphCache(const SkPaint& paint,
                      const SkSurfaceProps* surfaceProps,
                      const SkMatrix* matrix)
         : INHERITED(paint.detachCache(surfaceProps,
@@ skipping 15 matching lines @@
     SkAutoGlyphCacheNoGamma(const SkPaint& paint,
                             const SkSurfaceProps* surfaceProps,
                             const SkMatrix* matrix)
         : SkAutoGlyphCache(paint, surfaceProps, SkPaint::kNone_ScalerContextFlags, matrix)
     {}
 };
 #define SkAutoGlyphCache(...) SK_REQUIRE_LOCAL_VAR(SkAutoGlyphCache)
 #define SkAutoGlyphCacheNoGamma(...) SK_REQUIRE_LOCAL_VAR(SkAutoGlyphCacheNoGamma)
 
 #endif