Consider index8 a compressed config.

src/gpu/SkGr.cpp

 /*
  * Copyright 2010 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkGr.h"
 #include "SkColorFilter.h"
 #include "SkConfig8888.h"
@@ skipping 47 matching lines @@
     srcPI.fColorType = kN32_SkColorType;
     srcPI.fAlphaType = kPremul_SkAlphaType;
     srcPI.fPixels = ctable->lockColors();
     srcPI.fRowBytes = count * sizeof(SkPMColor);
 
     srcPI.convertPixelsTo(&dstPI, count, 1);
 
     ctable->unlockColors();
 
     // always skip a full 256 number of entries, even if we memcpy'd fewer
-    dst += kGrColorTableSize;
+    dst += 256 * sizeof(GrColor);
 
     if ((unsigned)bitmap.width() == bitmap.rowBytes()) {
         memcpy(dst, bitmap.getPixels(), bitmap.getSize());
     } else {
         // need to trim off the extra bytes per row
         size_t width = bitmap.width();
         size_t rowBytes = bitmap.rowBytes();
         const char* src = (const char*)bitmap.getPixels();
         for (int y = 0; y < bitmap.height(); y++) {
             memcpy(dst, src, width);
@@ skipping 199 matching lines @@
 
     const SkBitmap* bitmap = &origBitmap;
 
     GrTextureDesc desc;
     generate_bitmap_texture_desc(*bitmap, &desc);
 
     if (kIndex_8_SkColorType == bitmap->colorType()) {
         // build_compressed_data doesn't do npot->pot expansion
         // and paletted textures can't be sub-updated
         if (ctx->supportsIndex8PixelConfig(params, bitmap->width(), bitmap->height())) {
-            size_t imagesize = bitmap->width() * bitmap->height() + kGrColorTableSize;
-            SkAutoMalloc storage(imagesize);
+            size_t imageSize = GrCompressedFormatDataSize(kIndex_8_GrPixelConfig,
+                                                          bitmap->width(), bitmap->height());
+            SkAutoMalloc storage(imageSize);
 
             build_compressed_data(storage.get(), origBitmap);
 
             // our compressed data will be trimmed, so pass width() for its
             // "rowBytes", since they are the same now.
 
             if (cache) {
                 GrCacheID cacheID;
                 generate_bitmap_cache_id(origBitmap, &cacheID);
 
@@ skipping 317 matching lines @@
         if (shader->asNewEffect(context, skPaint, NULL, &paintColor, &effect) && NULL != effect) {
             grPaint->addColorEffect(effect)->unref();
             constantColor = false;
         }
     }
 
     // The grcolor is automatically set when calling asneweffect.
     // If the shader can be seen as an effect it returns true and adds its effect to the grpaint.
     SkPaint2GrPaintNoShader(context, skPaint, paintColor, constantColor, grPaint);
 }