Bug 682688 - FF6 Fix for moz-icon invalid generated icons. r=joe

modules/libpr0n/decoders/icon/win/nsIconChannel.cpp

@@ -452,10 +452,15 @@ static int GetColorTableSize(BITMAPINFOHEADER* aHeader)
   }
   case 16:
   case 32:
-    if (aHeader->biCompression == BI_RGB)
+    // If we have BI_BITFIELDS compression, we would normally need 3 DWORDS for
+    // the bitfields mask which would be stored in the color table; However, 
+    // we instead force the bitmap to request data of type BI_RGB so the color
+    // table should be of size 0.  
+    // Setting aHeader->biCompression = BI_RGB forces the later call to 
+    // GetDIBits to return to us BI_RGB data.
+    if (aHeader->biCompression == BI_BITFIELDS)
+      aHeader->biCompression = BI_RGB;
       colorTableSize = 0;
-    else if (aHeader->biCompression == BI_BITFIELDS)
-      colorTableSize = 3 * sizeof(DWORD);
     break;
   case 24:
     colorTableSize = 0;