Add query for block dimensions of a given format

src/utils/SkTextureCompressor.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 SkTextureCompressor_DEFINED
 #define SkTextureCompressor_DEFINED
 
@@ skipping 37 matching lines @@
     // are. The typedef is not meant to be used by clients of the API, but rather
     // allows SIMD optimized compression functions to be implemented.
     typedef bool (*CompressionProc)(uint8_t* dst, const uint8_t* src,
                                     int width, int height, int rowBytes);
 
     // Returns the blitter for the given compression format. Note, the blitter
     // is intended to be used with the proper input. I.e. if you try to blit
     // RGB source data into an R11 EAC texture, you're gonna have a bad time.
     SkBlitter* CreateBlitterForFormat(int width, int height, void* compressedBuffer,
                                       Format format);
+
+    // Returns the desired dimensions of the block size for the given format. These dimensions
+    // don't necessarily correspond to the hardware-specified dimensions, since there may
+    // be specialized algorithms that operate on multiple blocks at once. These dimensions
+    // reflect that optimization and return the appropriate operable dimensions.
+    void GetBlockDimensions(Format format, int* dimX, int* dimY);
 }
 
 #endif