Start the process of choosing the correct compression format

src/gpu/GrSWMaskHelper.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrSWMaskHelper_DEFINED
 #define GrSWMaskHelper_DEFINED
 
@@ skipping 24 matching lines @@
  *      draw one or more paths/rects specifying the required boolean ops
  *
  *   toTexture();   // to get it from the internal bitmap to the GPU
  *
  * The result of this process will be the final mask (on the GPU) in the
  * upper left hand corner of the texture.
  */
 class GrSWMaskHelper : SkNoncopyable {
 public:
     GrSWMaskHelper(GrContext* context)
-    : fContext(context) {
+    : fContext(context), fCompressMask(false) {
     }
 
     // set up the internal state in preparation for draws. Since many masks
     // may be accumulated in the helper during creation, "resultBounds"
     // allows the caller to specify the region of interest - to limit the
     // amount of work.
     bool init(const SkIRect& resultBounds, const SkMatrix* matrix);
 
     // Draw a single rect into the accumulation bitmap using the specified op
     void draw(const SkRect& rect, SkRegion::Op op,
@@ skipping 39 matching lines @@
                                          const SkIRect& rect);
 
 protected:
 private:
     GrContext*      fContext;
     SkMatrix        fMatrix;
     SkBitmap        fBM;
     SkDraw          fDraw;
     SkRasterClip    fRasterClip;
 
-#if GR_COMPRESS_ALPHA_MASK
+    // This flag says whether or not we should compress the mask. If
+    // it is true, then fCompressedFormat is always valid.
+    bool                        fCompressMask;
+
+    // This is the desired format within which to compress the
+    // texture. This value is only valid if fCompressMask is true.
     SkTextureCompressor::Format fCompressedFormat;
-#endif
 
     // Actually sends the texture data to the GPU. This is called from
     // toTexture with the data filled in depending on the texture config.
     void sendTextureData(GrTexture *texture, const GrTextureDesc& desc,
                          const void *data, int rowbytes);
 
     // Compresses the bitmap stored in fBM and sends the compressed data
     // to the GPU to be stored in 'texture' using sendTextureData.
     void compressTextureData(GrTexture *texture, const GrTextureDesc& desc);
 
     typedef SkNoncopyable INHERITED;
 };
 
 #endif // GrSWMaskHelper_DEFINED