Pass compressed blitters to our mask drawing algorithm

src/gpu/GrSWMaskHelper.h

Index: src/gpu/GrSWMaskHelper.h
diff --git a/src/gpu/GrSWMaskHelper.h b/src/gpu/GrSWMaskHelper.h
index 4c06786280a4b11087ef669fbd56072dc27d384d..ccd2df865e420038d056af10d254c5cfabdf4902 100644
--- a/src/gpu/GrSWMaskHelper.h
+++ b/src/gpu/GrSWMaskHelper.h
@@ -42,7 +42,8 @@ class GrDrawTarget;
 class GrSWMaskHelper : SkNoncopyable {
 public:
     GrSWMaskHelper(GrContext* context)
-    : fContext(context), fCompressMask(false) {
+    : fContext(context)
+    , fCompressionMode(kNone_CompressionMode) {
     }
 
     // set up the internal state in preparation for draws. Since many masks
@@ -94,7 +95,6 @@ public:
                                          GrDrawTarget* target,
                                          const SkIRect& rect);
 
-protected:
 private:
     GrContext*      fContext;
     SkMatrix        fMatrix;
@@ -102,12 +102,22 @@ private:
     SkDraw          fDraw;
     SkRasterClip    fRasterClip;
 
-    // This flag says whether or not we should compress the mask. If
-    // it is true, then fCompressedFormat is always valid.
-    bool                        fCompressMask;
+    // This enum says whether or not we should compress the mask:
+    // kNone_CompressionMode: compression is not supported on this device.
+    // kCompress_CompressionMode: compress the bitmap before it gets sent to the gpu
+    // kBlitter_CompressionMode: write to the bitmap using a special compressed blitter.
+    enum CompressionMode {
+        kNone_CompressionMode,
+        kCompress_CompressionMode,
+        kBlitter_CompressionMode,
+    } fCompressionMode;
+
+    // This is the buffer into which we store our compressed data. This buffer is
+    // only allocated (non-null) if fCompressionMode is kBlitter_CompressionMode
+    SkAutoMalloc fCompressedBuffer;
 
     // This is the desired format within which to compress the
-    // texture. This value is only valid if fCompressMask is true.
+    // texture. This value is only valid if fCompressionMode is not kNone_CompressionMode.
     SkTextureCompressor::Format fCompressedFormat;
 
     // Actually sends the texture data to the GPU. This is called from