SkColorTable locking serves no purpose anymore.

src/core/SkConfig8888.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBitmap.h"
 #include "SkCanvas.h"
 #include "SkConfig8888.h"
@@ skipping 136 matching lines @@
     const int width = srcInfo.width();
     const int height = srcInfo.height();
 
     // Handle fancy alpha swizzling if both are ARGB32
     if (4 == srcInfo.bytesPerPixel() && 4 == dstInfo.bytesPerPixel()) {
         SkDstPixelInfo dstPI;
         dstPI.fColorType = dstInfo.colorType();
         dstPI.fAlphaType = dstInfo.alphaType();
         dstPI.fPixels = dstPixels;
         dstPI.fRowBytes = dstRB;
-        
+
         SkSrcPixelInfo srcPI;
         srcPI.fColorType = srcInfo.colorType();
         srcPI.fAlphaType = srcInfo.alphaType();
         srcPI.fPixels = srcPixels;
         srcPI.fRowBytes = srcRB;
-        
+
         return srcPI.convertPixelsTo(&dstPI, width, height);
     }
 
     // If they agree on colorType and the alphaTypes are compatible, then we just memcpy.
     // Note: we've already taken care of 32bit colortypes above.
     if (srcInfo.colorType() == dstInfo.colorType()) {
         switch (srcInfo.colorType()) {
             case kRGB_565_SkColorType:
             case kAlpha_8_SkColorType:
                 break;
@@ skipping 15 matching lines @@
      *  are supported.
      */
 
     // Can no longer draw directly into 4444, but we can manually whack it for a few combinations
     if (kARGB_4444_SkColorType == dstInfo.colorType() &&
         (kN32_SkColorType == srcInfo.colorType() || kIndex_8_SkColorType == srcInfo.colorType())) {
         if (srcInfo.alphaType() == kUnpremul_SkAlphaType) {
             // Our method for converting to 4444 assumes premultiplied.
             return false;
         }
-        
+
         const SkPMColor* table = NULL;
         if (kIndex_8_SkColorType == srcInfo.colorType()) {
             if (NULL == ctable) {
                 return false;
             }
-            table = ctable->lockColors();
+            table = ctable->readColors();
         }
 
         for (int y = 0; y < height; ++y) {
             DITHER_4444_SCAN(y);
             SkPMColor16* SK_RESTRICT dstRow = (SkPMColor16*)dstPixels;
             if (table) {
                 const uint8_t* SK_RESTRICT srcRow = (const uint8_t*)srcPixels;
                 for (int x = 0; x < width; ++x) {
                     dstRow[x] = SkDitherARGB32To4444(table[srcRow[x]], DITHER_VALUE(x));
                 }
             } else {
                 const SkPMColor* SK_RESTRICT srcRow = (const SkPMColor*)srcPixels;
                 for (int x = 0; x < width; ++x) {
                     dstRow[x] = SkDitherARGB32To4444(srcRow[x], DITHER_VALUE(x));
                 }
             }
             dstPixels = (char*)dstPixels + dstRB;
             srcPixels = (const char*)srcPixels + srcRB;
         }
-        
-        if (table) {
-            ctable->unlockColors();
-        }
         return true;
     }
 
     if (dstInfo.alphaType() == kUnpremul_SkAlphaType) {
         // We do not support drawing to unpremultiplied bitmaps.
         return false;
     }
 
     // Final fall-back, draw with a canvas
     //
@@ skipping 11 matching lines @@
 
         SkPaint  paint;
         paint.setDither(true);
 
         canvas->clear(0);
         canvas->drawBitmap(bm, 0, 0, &paint);
         return true;
     }
 }