Skip composition of frames lacking a color map

Bug:68399117

Change-Id: I32f1d6856221b8a60130633edb69da2d2986c27c
(cherry picked from commit 0dc887f70eeea8d707cb426b96c6756edd1c607d)

static bool isGif(void* header, int header_size) {
 return !memcmp(GIF_STAMP, header, GIF_STAMP_LEN)
 || !memcmp(GIF87_STAMP, header, GIF_STAMP_LEN)
 || !memcmp(GIF89_STAMP, header, GIF_STAMP_LEN);
}

static bool isGif(void* header, int header_size) {
 return !memcmp(GIF_STAMP, header, GIF_STAMP_LEN)
 || !memcmp(GIF87_STAMP, header, GIF_STAMP_LEN)
 || !memcmp(GIF89_STAMP, header, GIF_STAMP_LEN);
}
