change SkColorTable to be immutable

src/images/SkImageDecoder_libgif.cpp

Index: src/images/SkImageDecoder_libgif.cpp
diff --git a/src/images/SkImageDecoder_libgif.cpp b/src/images/SkImageDecoder_libgif.cpp
index 1d25120da9c7585abbd002a16d724932d57d1595..ffec30bc05f73ecb615fd4b3dba992253f6fe526 100644
--- a/src/images/SkImageDecoder_libgif.cpp
+++ b/src/images/SkImageDecoder_libgif.cpp
@@ -225,9 +225,9 @@ bool SkGIFImageDecoder::onDecode(SkStream* sk_stream, SkBitmap* bm, Mode mode) {
                     return error_return(gif, *bm, "null cmap");
                 }
 
+                SkPMColor colorPtr[256]; // storage for worse-case

[scroggo, 2013/10/07 21:58:42]

worst*

[reed1, 2013/10/09 12:19:54]

Done.

                 colorCount = cmap->ColorCount;
-                SkColorTable* ctable = SkNEW_ARGS(SkColorTable, (colorCount));
-                SkPMColor* colorPtr = ctable->lockColors();
+                SkAlphaType alphaType = kOpaque_SkAlphaType;
                 for (int index = 0; index < colorCount; index++)
                     colorPtr[index] = SkPackARGB32(0xFF,
                                                    cmap->Colors[index].Red,
@@ -235,13 +235,15 @@ bool SkGIFImageDecoder::onDecode(SkStream* sk_stream, SkBitmap* bm, Mode mode) {
                                                    cmap->Colors[index].Blue);
 
                 transpIndex = find_transpIndex(temp_save, colorCount);
-                if (transpIndex < 0)
-                    ctable->setFlags(ctable->getFlags() | SkColorTable::kColorsAreOpaque_Flag);
-                else
+                if (transpIndex >= 0) {
+                    SkASSERT((unsigned)transpIndex < (unsigned)colorCount);
                     colorPtr[transpIndex] = 0; // ram in a transparent SkPMColor
-                ctable->unlockColors(true);
+                    alphaType = kPremul_SkAlphaType;
+                }
 
-                SkAutoUnref aurts(ctable);
+                SkAutoTUnref<SkColorTable> ctable(SkNEW_ARGS(SkColorTable,
+                                                  (colorPtr, colorCount,
+                                                   alphaType)));
                 if (!this->allocPixelRef(bm, ctable)) {
                     return error_return(gif, *bm, "allocPixelRef");
                 }