Make is_ktx safer

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 "SkGrPriv.h"
@@ skipping 69 matching lines @@
         // Does the data match the dimensions of the bitmap? If not,
         // then we don't know how to scale the image to match it...
         if (etc1_pkm_get_width(bytes) != (unsigned)expectedW ||
             etc1_pkm_get_height(bytes) != (unsigned)expectedH)
         {
             return kUnknown_GrPixelConfig;
         }
 
         *outStartOfDataToUpload = bytes + ETC_PKM_HEADER_SIZE;
         return kETC1_GrPixelConfig;
-    } else if (SkKTXFile::is_ktx(bytes)) {
+    } else if (SkKTXFile::is_ktx(bytes, data->size())) {
         SkKTXFile ktx(data);
 
         // Is it actually an ETC1 texture?
         if (!ktx.isCompressedFormat(SkTextureCompressor::kETC1_Format)) {
             return kUnknown_GrPixelConfig;
         }
 
         // Does the data match the dimensions of the bitmap? If not,
         // then we don't know how to scale the image to match it...
         if (ktx.width() != expectedW || ktx.height() != expectedH) {
@@ skipping 655 matching lines @@
             SkErrorInternals::SetError( kInvalidPaint_SkError,
                                         "Sorry, I don't understand the filtering "
                                         "mode you asked for.  Falling back to "
                                         "MIPMaps.");
             textureFilterMode = GrTextureParams::kMipMap_FilterMode;
             break;
 
     }
     return textureFilterMode;
 }