Add sanity check to GrAtlasTextBlob

src/gpu/GrAtlasTextBlob.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrAtlasTextBlob_DEFINED
 #define GrAtlasTextBlob_DEFINED
 
 #include "GrBatchAtlas.h"
 #include "GrBatchFontCache.h"
+#include "GrColor.h"
 #include "SkDescriptor.h"
 #include "SkMaskFilter.h"
 #include "GrMemoryPool.h"
+#include "SkSurfaceProps.h"
 #include "SkTInternalLList.h"
 
+// With this flag enabled, the GrAtlasTextContext will, as a sanity check, regenerate every blob
+// that comes in to verify the integrity of its cache
+//#define CACHE_SANITY_CHECK // VERY SLOW
+
 /*
  * A GrAtlasTextBlob contains a fully processed SkTextBlob, suitable for nearly immediate drawing
  * on the GPU.  These are initially created with valid positions and colors, but invalid
  * texture coordinates.  The GrAtlasTextBlob itself has a few Blob-wide properties, and also
  * consists of a number of runs.  Runs inside a blob are flushed individually so they can be
  * reordered.
  *
  * The only thing(aside from a memcopy) required to flush a GrAtlasTextBlob is to ensure that
  * the GrAtlas will not evict anything the Blob needs.
  *
  * Note: This struct should really be named GrCachedAtasTextBlob, but that is too verbose.
+ *
+ * *WARNING* If you add new fields to this struct, then you may need to to update AssertEqual
  */
 struct GrAtlasTextBlob : public SkRefCnt {
     SK_DECLARE_INTERNAL_LLIST_INTERFACE(GrAtlasTextBlob);
 
     /*
      * Each Run inside of the blob can have its texture coordinates regenerated if required.
      * To determine if regeneration is necessary, fAtlasGeneration is used.  If there have been
      * any evictions inside of the atlas, then we will simply regenerate Runs.  We could track
      * this at a more fine grained level, but its not clear if this is worth it, as evictions
      * should be fairly rare.
@@ skipping 165 matching lines @@
 
     void* operator new(size_t, void* p) { return p; }
     void operator delete(void* target, void* placement) {
         ::operator delete(target, placement);
     }
 
     bool hasDistanceField() const { return SkToBool(fTextType & kHasDistanceField_TextType); }
     bool hasBitmap() const { return SkToBool(fTextType & kHasBitmap_TextType); }
     void setHasDistanceField() { fTextType |= kHasDistanceField_TextType; }
     void setHasBitmap() { fTextType |= kHasBitmap_TextType; }
+
+#ifdef CACHE_SANITY_CHECK
+    static void AssertEqual(const GrAtlasTextBlob&, const GrAtlasTextBlob&);
+    size_t fSize;
+#endif
 };
 
 #endif