Revert "net: workaround compression leaks"

This reverts r151502.

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@151517 0039d316-1c4b-4281-b951-d872f2087c98

6 files changed, 31 insertions, 708 deletions

diff --git a/third_party/zlib/README.chromium b/third_party/zlib/README.chromium
index 81d20ef..aa5d4a5 100644
--- a/third_party/zlib/README.chromium
+++ b/third_party/zlib/README.chromium
@@ -16,6 +16,3 @@ A few minor changes, all marked with "Google":
 - Added 'mozzconf.h' to mangle the function names.
 - Added an #ifdef to prevent zlib.h from mangling its functions.
 The 'google.patch' file represents our changes from the original zlib-1.2.5.
-
-A more significant change to support mixed-source data compression. See
-crbug.com/139744 and mixed-source.patch.
diff --git a/third_party/zlib/deflate.c b/third_party/zlib/deflate.c
index e419858..5c4022f 100644
--- a/third_party/zlib/deflate.c
+++ b/third_party/zlib/deflate.c
@@ -70,15 +70,14 @@ typedef enum {
     finish_done     /* finish done, accept no more input or output */
 } block_state;
 
-typedef block_state (*compress_func) OF((deflate_state *s, int flush,
-                                         int clas));
+typedef block_state (*compress_func) OF((deflate_state *s, int flush));
 /* Compression function. Returns the block state after the call. */
 
 local void fill_window    OF((deflate_state *s));
-local block_state deflate_stored OF((deflate_state *s, int flush, int clas));
-local block_state deflate_fast   OF((deflate_state *s, int flush, int clas));
+local block_state deflate_stored OF((deflate_state *s, int flush));
+local block_state deflate_fast   OF((deflate_state *s, int flush));
 #ifndef FASTEST
-local block_state deflate_slow   OF((deflate_state *s, int flush, int clas));
+local block_state deflate_slow   OF((deflate_state *s, int flush));
 #endif
 local block_state deflate_rle    OF((deflate_state *s, int flush));
 local block_state deflate_huff   OF((deflate_state *s, int flush));
@@ -88,9 +87,9 @@ local void flush_pending  OF((z_streamp strm));
 local int read_buf        OF((z_streamp strm, Bytef *buf, unsigned size));
 #ifdef ASMV
       void match_init OF((void)); /* asm code initialization */
-      uInt longest_match  OF((deflate_state *s, IPos cur_match, int clas));
+      uInt longest_match  OF((deflate_state *s, IPos cur_match));
 #else
-local uInt longest_match  OF((deflate_state *s, IPos cur_match, int clas));
+local uInt longest_match  OF((deflate_state *s, IPos cur_match));
 #endif
 
 #ifdef DEBUG
@@ -282,9 +281,6 @@ int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,
     s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte));
     s->prev   = (Posf *)  ZALLOC(strm, s->w_size, sizeof(Pos));
     s->head   = (Posf *)  ZALLOC(strm, s->hash_size, sizeof(Pos));
-    s->class_bitmap = NULL;
-    zmemzero(&s->cookie_locations, sizeof(s->cookie_locations));
-    strm->clas = 0;
 
     s->high_water = 0;      /* nothing written to s->window yet */
 
@@ -371,8 +367,6 @@ int ZEXPORT deflateReset (strm)
     s = (deflate_state *)strm->state;
     s->pending = 0;
     s->pending_out = s->pending_buf;
-    ZFREE(strm, s->class_bitmap);
-    s->class_bitmap = NULL;
 
     if (s->wrap < 0) {
         s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */
@@ -823,26 +817,9 @@ int ZEXPORT deflate (strm, flush)
         (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) {
         block_state bstate;
 
-        if (strm->clas && s->class_bitmap == NULL) {
-            /* This is the first time that we have seen alternative class
-             * data. All data up till this point has been standard class. */
-            s->class_bitmap = (Bytef*) ZALLOC(strm, s->w_size/4, sizeof(Byte));
-            zmemzero(s->class_bitmap, s->w_size/4);
-        }
-
-        if (strm->clas && s->strategy == Z_RLE) {
-            /* We haven't patched deflate_rle. */
-            ERR_RETURN(strm, Z_BUF_ERROR);
-        }
-
-        if (s->strategy == Z_HUFFMAN_ONLY) {
-            bstate = deflate_huff(s, flush);
-        } else if (s->strategy == Z_RLE) {
-            bstate = deflate_rle(s, flush);
-        } else {
-            bstate = (*(configuration_table[s->level].func))
-                (s, flush, strm->clas);
-        }
+        bstate = s->strategy == Z_HUFFMAN_ONLY ? deflate_huff(s, flush) :
+                    (s->strategy == Z_RLE ? deflate_rle(s, flush) :
+                        (*(configuration_table[s->level].func))(s, flush));
 
         if (bstate == finish_started || bstate == finish_done) {
             s->status = FINISH_STATE;
@@ -1069,57 +1046,6 @@ local void lm_init (s)
 #endif
 }
 
-/* class_set sets bits [offset,offset+len) in s->class_bitmap to either 1 (if
- * class != 0) or 0 (otherwise). */
-local void class_set(s, offset, len, clas)
-    deflate_state *s;
-    IPos offset;
-    uInt len;
-    int clas;
-{
-    IPos byte = offset >> 3;
-    IPos bit = offset & 7;
-    Bytef class_byte_value = clas ? 0xff : 0x00;
-    Bytef class_bit_value = clas ? 1 : 0;
-    static const Bytef mask[8] = {0xfe, 0xfd, 0xfb, 0xf7,
-                                  0xef, 0xdf, 0xbf, 0x7f};
-
-    if (bit) {
-        while (len) {
-            s->class_bitmap[byte] &= mask[bit];
-            s->class_bitmap[byte] |= class_bit_value << bit;
-            bit++;
-            len--;
-            if (bit == 8) {
-                bit = 0;
-                byte++;
-                break;
-            }
-        }
-    }
-
-    while (len >= 8) {
-        s->class_bitmap[byte++] = class_byte_value;
-        len -= 8;
-    }
-
-    while (len) {
-            s->class_bitmap[byte] &= mask[bit];
-            s->class_bitmap[byte] |= class_bit_value << bit;
-            bit++;
-            len--;
-    }
-}
-
-local int class_at(s, window_offset)
-    deflate_state *s;
-    IPos window_offset;
-{
-    IPos byte = window_offset >> 3;
-    IPos bit = window_offset & 7;
-    return (s->class_bitmap[byte] >> bit) & 1;
-}
-
 #ifndef FASTEST
 /* ===========================================================================
  * Set match_start to the longest match starting at the given string and
@@ -1134,10 +1060,9 @@ local int class_at(s, window_offset)
 /* For 80x86 and 680x0, an optimized version will be provided in match.asm or
  * match.S. The code will be functionally equivalent.
  */
-local uInt longest_match(s, cur_match, clas)
+local uInt longest_match(s, cur_match)
     deflate_state *s;
     IPos cur_match;                             /* current match */
-    int clas;
 {
     unsigned chain_length = s->max_chain_length;/* max hash chain length */
     register Bytef *scan = s->window + s->strstart; /* current string */
@@ -1185,9 +1110,6 @@ local uInt longest_match(s, cur_match, clas)
     do {
         Assert(cur_match < s->strstart, "no future");
         match = s->window + cur_match;
-        /* If the matched data is in the wrong class, skip it. */
-        if (s->class_bitmap && class_at(s, cur_match) != clas)
-            continue;
 
         /* Skip to next match if the match length cannot increase
          * or if the match length is less than 2.  Note that the checks below
@@ -1230,8 +1152,6 @@ local uInt longest_match(s, cur_match, clas)
         len = (MAX_MATCH - 1) - (int)(strend-scan);
         scan = strend - (MAX_MATCH-1);
 
-#error "UNALIGNED_OK hasn't been patched."
-
 #else /* UNALIGNED_OK */
 
         if (match[best_len]   != scan_end  ||
@@ -1248,23 +1168,15 @@ local uInt longest_match(s, cur_match, clas)
         scan += 2, match++;
         Assert(*scan == *match, "match[2]?");
 
-        if (!s->class_bitmap) {
-            /* We check for insufficient lookahead only every 8th comparison;
-             * the 256th check will be made at strstart+258.
-             */
-            do {
-            } while (*++scan == *++match && *++scan == *++match &&
-                     *++scan == *++match && *++scan == *++match &&
-                     *++scan == *++match && *++scan == *++match &&
-                     *++scan == *++match && *++scan == *++match &&
-                     scan < strend);
-        } else {
-            /* We have to be mindful of the class of the data and not stray. */
-            do {
-            } while (*++scan == *++match &&
-                     class_at(s, match - s->window) == clas &&
-                     scan < strend);
-        }
+        /* We check for insufficient lookahead only every 8th comparison;
+         * the 256th check will be made at strstart+258.
+         */
+        do {
+        } while (*++scan == *++match && *++scan == *++match &&
+                 *++scan == *++match && *++scan == *++match &&
+                 *++scan == *++match && *++scan == *++match &&
+                 *++scan == *++match && *++scan == *++match &&
+                 scan < strend);
 
         Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
 
@@ -1292,67 +1204,20 @@ local uInt longest_match(s, cur_match, clas)
 }
 #endif /* ASMV */
 
-/* cookie_match is a replacement for longest_match in the case of cookie data.
- * Here we only wish to match the entire value so trying the partial matches in
- * longest_match is both wasteful and often fails to find the correct match.
- *
- * So we take the djb2 hash of the cookie and look up the last position for a
- * match in a special hash table. */
-local uInt cookie_match(s, start, len)
-    deflate_state *s;
-    IPos start;
-    unsigned len;
-{
-    unsigned hash = 5381;
-    Bytef *str = s->window + start;
-    unsigned i;
-    IPos cookie_location;
-
-    if (len >= MAX_MATCH)
-        return 0;
-
-    for (i = 0; i < len; i++)
-        hash = ((hash << 5) + hash) + str[i];
-
-    hash &= Z_COOKIE_HASH_MASK;
-    cookie_location = s->cookie_locations[hash];
-    s->cookie_locations[hash] = start;
-    s->match_start = 0;
-    if (cookie_location &&
-        (start - cookie_location) > len &&
-        (start - cookie_location) < MAX_DIST(s) &&
-        len <= s->lookahead) {
-        for (i = 0; i < len; i++) {
-            if (s->window[start+i] != s->window[cookie_location+i] ||
-                class_at(s, cookie_location+i) != 1) {
-                return 0;
-            }
-        }
-        s->match_start = cookie_location;
-        return len;
-    }
-
-    return 0;
-}
-
-
 #else /* FASTEST */
 
 /* ---------------------------------------------------------------------------
  * Optimized version for FASTEST only
  */
-local uInt longest_match(s, cur_match, clas)
+local uInt longest_match(s, cur_match)
     deflate_state *s;
     IPos cur_match;                             /* current match */
-    int clas;
 {
     register Bytef *scan = s->window + s->strstart; /* current string */
     register Bytef *match;                       /* matched string */
     register int len;                           /* length of current match */
     register Bytef *strend = s->window + s->strstart + MAX_MATCH;
 
-#error "This code not patched"
-
     /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
      * It is easy to get rid of this optimization if necessary.
      */
@@ -1495,21 +1360,6 @@ local void fill_window(s)
                  */
             } while (--n);
 #endif
-
-            for (n = 0; n < Z_COOKIE_HASH_SIZE; n++) {
-                if (s->cookie_locations[n] > wsize) {
-                    s->cookie_locations[n] -= wsize;
-                } else {
-                    s->cookie_locations[n] = 0;
-                }
-            }
-
-            if (s->class_bitmap) {
-                zmemcpy(s->class_bitmap, s->class_bitmap + s->w_size/8,
-                        s->w_size/8);
-                zmemzero(s->class_bitmap + s->w_size/8, s->w_size/8);
-            }
-
             more += wsize;
         }
         if (s->strm->avail_in == 0) return;
@@ -1528,9 +1378,6 @@ local void fill_window(s)
         Assert(more >= 2, "more < 2");
 
         n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more);
-        if (s->class_bitmap != NULL) {
-            class_set(s, s->strstart + s->lookahead, n, s->strm->clas);
-        }
         s->lookahead += n;
 
         /* Initialize the hash value now that we have some input: */
@@ -1612,10 +1459,9 @@ local void fill_window(s)
  * NOTE: this function should be optimized to avoid extra copying from
  * window to pending_buf.
  */
-local block_state deflate_stored(s, flush, clas)
+local block_state deflate_stored(s, flush)
     deflate_state *s;
     int flush;
-    int clas;
 {
     /* Stored blocks are limited to 0xffff bytes, pending_buf is limited
      * to pending_buf_size, and each stored block has a 5 byte header:
@@ -1671,19 +1517,13 @@ local block_state deflate_stored(s, flush, clas)
  * new strings in the dictionary only for unmatched strings or for short
  * matches. It is used only for the fast compression options.
  */
-local block_state deflate_fast(s, flush, clas)
+local block_state deflate_fast(s, flush)
     deflate_state *s;
     int flush;
-    int clas;
 {
     IPos hash_head;       /* head of the hash chain */
     int bflush;           /* set if current block must be flushed */
 
-    if (clas != 0) {
-        /* We haven't patched this code for alternative class data. */
-        return Z_BUF_ERROR;
-    }
-
     for (;;) {
         /* Make sure that we always have enough lookahead, except
          * at the end of the input file. We need MAX_MATCH bytes
@@ -1714,7 +1554,7 @@ local block_state deflate_fast(s, flush, clas)
              * of window index 0 (in particular we have to avoid a match
              * of the string with itself at the start of the input file).
              */
-            s->match_length = longest_match (s, hash_head, clas);
+            s->match_length = longest_match (s, hash_head);
             /* longest_match() sets match_start */
         }
         if (s->match_length >= MIN_MATCH) {
@@ -1773,25 +1613,12 @@ local block_state deflate_fast(s, flush, clas)
  * evaluation for matches: a match is finally adopted only if there is
  * no better match at the next window position.
  */
-local block_state deflate_slow(s, flush, clas)
+local block_state deflate_slow(s, flush)
     deflate_state *s;
     int flush;
-    int clas;
 {
     IPos hash_head;          /* head of hash chain */
     int bflush;              /* set if current block must be flushed */
-    uInt input_length ;
-    int first = 1;           /* first says whether this is the first iteration
-                                of the loop, below. */
-
-    if (clas == Z_CLASS_COOKIE) {
-        if (s->lookahead) {
-            /* Alternative class data must always be presented at the beginning
-             * of a block. */
-            return Z_BUF_ERROR;
-        }
-        input_length = s->strm->avail_in;
-    }
 
     /* Process the input block. */
     for (;;) {
@@ -1821,18 +1648,13 @@ local block_state deflate_slow(s, flush, clas)
         s->prev_length = s->match_length, s->prev_match = s->match_start;
         s->match_length = MIN_MATCH-1;
 
-        if (clas == Z_CLASS_COOKIE && first) {
-            s->match_length = cookie_match(s, s->strstart, input_length);
-        } else if (clas == Z_CLASS_STANDARD &&
-                   hash_head != NIL &&
-                   s->prev_length < s->max_lazy_match &&
-                   s->strstart - hash_head <= MAX_DIST(s)) {
+        if (hash_head != NIL && s->prev_length < s->max_lazy_match &&
+            s->strstart - hash_head <= MAX_DIST(s)) {
             /* To simplify the code, we prevent matches with the string
              * of window index 0 (in particular we have to avoid a match
              * of the string with itself at the start of the input file).
              */
-            s->match_length = longest_match (s, hash_head, clas);
-
+            s->match_length = longest_match (s, hash_head);
             /* longest_match() sets match_start */
 
             if (s->match_length <= 5 && (s->strategy == Z_FILTERED
@@ -1851,22 +1673,7 @@ local block_state deflate_slow(s, flush, clas)
         /* If there was a match at the previous step and the current
          * match is not better, output the previous match:
          */
-        first = 0;
-        if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length &&
-            /* We will only accept an exact match for Z_CLASS_COOKIE data and
-             * we won't match Z_CLASS_HUFFMAN_ONLY data at all. */
-            (clas == Z_CLASS_STANDARD || (clas == Z_CLASS_COOKIE &&
-                            s->prev_length == input_length &&
-                            s->prev_match > 0 &&
-                            /* We require that a Z_CLASS_COOKIE match be
-                             * preceded by either a semicolon (which cannot be
-                             * part of a cookie), or non-cookie data. This is
-                             * to prevent
-                             * a cookie from being a prefix of another.
-                             * spdy_framer.cc ensures that cookies are always
-                             * terminated by a semicolon. */
-                            (class_at(s, s->prev_match-1) == Z_CLASS_STANDARD ||
-                             *(s->window + s->prev_match-1) == ';')))) {
+        if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) {
             uInt max_insert = s->strstart + s->lookahead - MIN_MATCH;
             /* Do not insert strings in hash table beyond this. */
 
diff --git a/third_party/zlib/deflate.h b/third_party/zlib/deflate.h
index 83b4602..cbf0d1e 100644
--- a/third_party/zlib/deflate.h
+++ b/third_party/zlib/deflate.h
@@ -91,9 +91,6 @@ typedef unsigned IPos;
  * save space in the various tables. IPos is used only for parameter passing.
  */
 
-#define Z_COOKIE_HASH_SIZE 64
-#define Z_COOKIE_HASH_MASK (Z_COOKIE_HASH_SIZE-1)
-
 typedef struct internal_state {
     z_streamp strm;      /* pointer back to this zlib stream */
     int   status;        /* as the name implies */
@@ -142,8 +139,6 @@ typedef struct internal_state {
     uInt  hash_mask;      /* hash_size-1 */
 
     uInt  hash_shift;
-    Bytef *class_bitmap;  /* bitmap of class for each byte in window */
-    IPos cookie_locations[Z_COOKIE_HASH_SIZE];
     /* Number of bits by which ins_h must be shifted at each input
      * step. It must be such that after MIN_MATCH steps, the oldest
      * byte no longer takes part in the hash key, that is:
diff --git a/third_party/zlib/mixed-source.patch b/third_party/zlib/mixed-source.patch
deleted file mode 100644
index 4f7294e..0000000
--- a/third_party/zlib/mixed-source.patch
+++ /dev/null
@@ -1,469 +0,0 @@
-diff --git a/third_party/zlib/deflate.c b/third_party/zlib/deflate.c
-index 5c4022f..e419858 100644
---- a/third_party/zlib/deflate.c
-+++ b/third_party/zlib/deflate.c
-@@ -70,14 +70,15 @@ typedef enum {
-     finish_done     /* finish done, accept no more input or output */
- } block_state;
- 
--typedef block_state (*compress_func) OF((deflate_state *s, int flush));
-+typedef block_state (*compress_func) OF((deflate_state *s, int flush,
-+                                         int clas));
- /* Compression function. Returns the block state after the call. */
- 
- local void fill_window    OF((deflate_state *s));
--local block_state deflate_stored OF((deflate_state *s, int flush));
--local block_state deflate_fast   OF((deflate_state *s, int flush));
-+local block_state deflate_stored OF((deflate_state *s, int flush, int clas));
-+local block_state deflate_fast   OF((deflate_state *s, int flush, int clas));
- #ifndef FASTEST
--local block_state deflate_slow   OF((deflate_state *s, int flush));
-+local block_state deflate_slow   OF((deflate_state *s, int flush, int clas));
- #endif
- local block_state deflate_rle    OF((deflate_state *s, int flush));
- local block_state deflate_huff   OF((deflate_state *s, int flush));
-@@ -87,9 +88,9 @@ local void flush_pending  OF((z_streamp strm));
- local int read_buf        OF((z_streamp strm, Bytef *buf, unsigned size));
- #ifdef ASMV
-       void match_init OF((void)); /* asm code initialization */
--      uInt longest_match  OF((deflate_state *s, IPos cur_match));
-+      uInt longest_match  OF((deflate_state *s, IPos cur_match, int clas));
- #else
--local uInt longest_match  OF((deflate_state *s, IPos cur_match));
-+local uInt longest_match  OF((deflate_state *s, IPos cur_match, int clas));
- #endif
- 
- #ifdef DEBUG
-@@ -281,6 +282,9 @@ int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,
-     s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte));
-     s->prev   = (Posf *)  ZALLOC(strm, s->w_size, sizeof(Pos));
-     s->head   = (Posf *)  ZALLOC(strm, s->hash_size, sizeof(Pos));
-+    s->class_bitmap = NULL;
-+    zmemzero(&s->cookie_locations, sizeof(s->cookie_locations));
-+    strm->clas = 0;
- 
-     s->high_water = 0;      /* nothing written to s->window yet */
- 
-@@ -367,6 +371,8 @@ int ZEXPORT deflateReset (strm)
-     s = (deflate_state *)strm->state;
-     s->pending = 0;
-     s->pending_out = s->pending_buf;
-+    ZFREE(strm, s->class_bitmap);
-+    s->class_bitmap = NULL;
- 
-     if (s->wrap < 0) {
-         s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */
-@@ -817,9 +823,26 @@ int ZEXPORT deflate (strm, flush)
-         (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) {
-         block_state bstate;
- 
--        bstate = s->strategy == Z_HUFFMAN_ONLY ? deflate_huff(s, flush) :
--                    (s->strategy == Z_RLE ? deflate_rle(s, flush) :
--                        (*(configuration_table[s->level].func))(s, flush));
-+        if (strm->clas && s->class_bitmap == NULL) {
-+            /* This is the first time that we have seen alternative class
-+             * data. All data up till this point has been standard class. */
-+            s->class_bitmap = (Bytef*) ZALLOC(strm, s->w_size/4, sizeof(Byte));
-+            zmemzero(s->class_bitmap, s->w_size/4);
-+        }
-+
-+        if (strm->clas && s->strategy == Z_RLE) {
-+            /* We haven't patched deflate_rle. */
-+            ERR_RETURN(strm, Z_BUF_ERROR);
-+        }
-+
-+        if (s->strategy == Z_HUFFMAN_ONLY) {
-+            bstate = deflate_huff(s, flush);
-+        } else if (s->strategy == Z_RLE) {
-+            bstate = deflate_rle(s, flush);
-+        } else {
-+            bstate = (*(configuration_table[s->level].func))
-+                (s, flush, strm->clas);
-+        }
- 
-         if (bstate == finish_started || bstate == finish_done) {
-             s->status = FINISH_STATE;
-@@ -1046,6 +1069,57 @@ local void lm_init (s)
- #endif
- }
- 
-+/* class_set sets bits [offset,offset+len) in s->class_bitmap to either 1 (if
-+ * class != 0) or 0 (otherwise). */
-+local void class_set(s, offset, len, clas)
-+    deflate_state *s;
-+    IPos offset;
-+    uInt len;
-+    int clas;
-+{
-+    IPos byte = offset >> 3;
-+    IPos bit = offset & 7;
-+    Bytef class_byte_value = clas ? 0xff : 0x00;
-+    Bytef class_bit_value = clas ? 1 : 0;
-+    static const Bytef mask[8] = {0xfe, 0xfd, 0xfb, 0xf7,
-+                                  0xef, 0xdf, 0xbf, 0x7f};
-+
-+    if (bit) {
-+        while (len) {
-+            s->class_bitmap[byte] &= mask[bit];
-+            s->class_bitmap[byte] |= class_bit_value << bit;
-+            bit++;
-+            len--;
-+            if (bit == 8) {
-+                bit = 0;
-+                byte++;
-+                break;
-+            }
-+        }
-+    }
-+
-+    while (len >= 8) {
-+        s->class_bitmap[byte++] = class_byte_value;
-+        len -= 8;
-+    }
-+
-+    while (len) {
-+            s->class_bitmap[byte] &= mask[bit];
-+            s->class_bitmap[byte] |= class_bit_value << bit;
-+            bit++;
-+            len--;
-+    }
-+}
-+
-+local int class_at(s, window_offset)
-+    deflate_state *s;
-+    IPos window_offset;
-+{
-+    IPos byte = window_offset >> 3;
-+    IPos bit = window_offset & 7;
-+    return (s->class_bitmap[byte] >> bit) & 1;
-+}
-+
- #ifndef FASTEST
- /* ===========================================================================
-  * Set match_start to the longest match starting at the given string and
-@@ -1060,9 +1134,10 @@ local void lm_init (s)
- /* For 80x86 and 680x0, an optimized version will be provided in match.asm or
-  * match.S. The code will be functionally equivalent.
-  */
--local uInt longest_match(s, cur_match)
-+local uInt longest_match(s, cur_match, clas)
-     deflate_state *s;
-     IPos cur_match;                             /* current match */
-+    int clas;
- {
-     unsigned chain_length = s->max_chain_length;/* max hash chain length */
-     register Bytef *scan = s->window + s->strstart; /* current string */
-@@ -1110,6 +1185,9 @@ local uInt longest_match(s, cur_match)
-     do {
-         Assert(cur_match < s->strstart, "no future");
-         match = s->window + cur_match;
-+        /* If the matched data is in the wrong class, skip it. */
-+        if (s->class_bitmap && class_at(s, cur_match) != clas)
-+            continue;
- 
-         /* Skip to next match if the match length cannot increase
-          * or if the match length is less than 2.  Note that the checks below
-@@ -1152,6 +1230,8 @@ local uInt longest_match(s, cur_match)
-         len = (MAX_MATCH - 1) - (int)(strend-scan);
-         scan = strend - (MAX_MATCH-1);
- 
-+#error "UNALIGNED_OK hasn't been patched."
-+
- #else /* UNALIGNED_OK */
- 
-         if (match[best_len]   != scan_end  ||
-@@ -1168,15 +1248,23 @@ local uInt longest_match(s, cur_match)
-         scan += 2, match++;
-         Assert(*scan == *match, "match[2]?");
- 
--        /* We check for insufficient lookahead only every 8th comparison;
--         * the 256th check will be made at strstart+258.
--         */
--        do {
--        } while (*++scan == *++match && *++scan == *++match &&
--                 *++scan == *++match && *++scan == *++match &&
--                 *++scan == *++match && *++scan == *++match &&
--                 *++scan == *++match && *++scan == *++match &&
--                 scan < strend);
-+        if (!s->class_bitmap) {
-+            /* We check for insufficient lookahead only every 8th comparison;
-+             * the 256th check will be made at strstart+258.
-+             */
-+            do {
-+            } while (*++scan == *++match && *++scan == *++match &&
-+                     *++scan == *++match && *++scan == *++match &&
-+                     *++scan == *++match && *++scan == *++match &&
-+                     *++scan == *++match && *++scan == *++match &&
-+                     scan < strend);
-+        } else {
-+            /* We have to be mindful of the class of the data and not stray. */
-+            do {
-+            } while (*++scan == *++match &&
-+                     class_at(s, match - s->window) == clas &&
-+                     scan < strend);
-+        }
- 
-         Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
- 
-@@ -1204,20 +1292,67 @@ local uInt longest_match(s, cur_match)
- }
- #endif /* ASMV */
- 
-+/* cookie_match is a replacement for longest_match in the case of cookie data.
-+ * Here we only wish to match the entire value so trying the partial matches in
-+ * longest_match is both wasteful and often fails to find the correct match.
-+ *
-+ * So we take the djb2 hash of the cookie and look up the last position for a
-+ * match in a special hash table. */
-+local uInt cookie_match(s, start, len)
-+    deflate_state *s;
-+    IPos start;
-+    unsigned len;
-+{
-+    unsigned hash = 5381;
-+    Bytef *str = s->window + start;
-+    unsigned i;
-+    IPos cookie_location;
-+
-+    if (len >= MAX_MATCH)
-+        return 0;
-+
-+    for (i = 0; i < len; i++)
-+        hash = ((hash << 5) + hash) + str[i];
-+
-+    hash &= Z_COOKIE_HASH_MASK;
-+    cookie_location = s->cookie_locations[hash];
-+    s->cookie_locations[hash] = start;
-+    s->match_start = 0;
-+    if (cookie_location &&
-+        (start - cookie_location) > len &&
-+        (start - cookie_location) < MAX_DIST(s) &&
-+        len <= s->lookahead) {
-+        for (i = 0; i < len; i++) {
-+            if (s->window[start+i] != s->window[cookie_location+i] ||
-+                class_at(s, cookie_location+i) != 1) {
-+                return 0;
-+            }
-+        }
-+        s->match_start = cookie_location;
-+        return len;
-+    }
-+
-+    return 0;
-+}
-+
-+
- #else /* FASTEST */
- 
- /* ---------------------------------------------------------------------------
-  * Optimized version for FASTEST only
-  */
--local uInt longest_match(s, cur_match)
-+local uInt longest_match(s, cur_match, clas)
-     deflate_state *s;
-     IPos cur_match;                             /* current match */
-+    int clas;
- {
-     register Bytef *scan = s->window + s->strstart; /* current string */
-     register Bytef *match;                       /* matched string */
-     register int len;                           /* length of current match */
-     register Bytef *strend = s->window + s->strstart + MAX_MATCH;
- 
-+#error "This code not patched"
-+
-     /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
-      * It is easy to get rid of this optimization if necessary.
-      */
-@@ -1360,6 +1495,21 @@ local void fill_window(s)
-                  */
-             } while (--n);
- #endif
-+
-+            for (n = 0; n < Z_COOKIE_HASH_SIZE; n++) {
-+                if (s->cookie_locations[n] > wsize) {
-+                    s->cookie_locations[n] -= wsize;
-+                } else {
-+                    s->cookie_locations[n] = 0;
-+                }
-+            }
-+
-+            if (s->class_bitmap) {
-+                zmemcpy(s->class_bitmap, s->class_bitmap + s->w_size/8,
-+                        s->w_size/8);
-+                zmemzero(s->class_bitmap + s->w_size/8, s->w_size/8);
-+            }
-+
-             more += wsize;
-         }
-         if (s->strm->avail_in == 0) return;
-@@ -1378,6 +1528,9 @@ local void fill_window(s)
-         Assert(more >= 2, "more < 2");
- 
-         n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more);
-+        if (s->class_bitmap != NULL) {
-+            class_set(s, s->strstart + s->lookahead, n, s->strm->clas);
-+        }
-         s->lookahead += n;
- 
-         /* Initialize the hash value now that we have some input: */
-@@ -1459,9 +1612,10 @@ local void fill_window(s)
-  * NOTE: this function should be optimized to avoid extra copying from
-  * window to pending_buf.
-  */
--local block_state deflate_stored(s, flush)
-+local block_state deflate_stored(s, flush, clas)
-     deflate_state *s;
-     int flush;
-+    int clas;
- {
-     /* Stored blocks are limited to 0xffff bytes, pending_buf is limited
-      * to pending_buf_size, and each stored block has a 5 byte header:
-@@ -1517,13 +1671,19 @@ local block_state deflate_stored(s, flush)
-  * new strings in the dictionary only for unmatched strings or for short
-  * matches. It is used only for the fast compression options.
-  */
--local block_state deflate_fast(s, flush)
-+local block_state deflate_fast(s, flush, clas)
-     deflate_state *s;
-     int flush;
-+    int clas;
- {
-     IPos hash_head;       /* head of the hash chain */
-     int bflush;           /* set if current block must be flushed */
- 
-+    if (clas != 0) {
-+        /* We haven't patched this code for alternative class data. */
-+        return Z_BUF_ERROR;
-+    }
-+
-     for (;;) {
-         /* Make sure that we always have enough lookahead, except
-          * at the end of the input file. We need MAX_MATCH bytes
-@@ -1554,7 +1714,7 @@ local block_state deflate_fast(s, flush)
-              * of window index 0 (in particular we have to avoid a match
-              * of the string with itself at the start of the input file).
-              */
--            s->match_length = longest_match (s, hash_head);
-+            s->match_length = longest_match (s, hash_head, clas);
-             /* longest_match() sets match_start */
-         }
-         if (s->match_length >= MIN_MATCH) {
-@@ -1613,12 +1773,25 @@ local block_state deflate_fast(s, flush)
-  * evaluation for matches: a match is finally adopted only if there is
-  * no better match at the next window position.
-  */
--local block_state deflate_slow(s, flush)
-+local block_state deflate_slow(s, flush, clas)
-     deflate_state *s;
-     int flush;
-+    int clas;
- {
-     IPos hash_head;          /* head of hash chain */
-     int bflush;              /* set if current block must be flushed */
-+    uInt input_length ;
-+    int first = 1;           /* first says whether this is the first iteration
-+                                of the loop, below. */
-+
-+    if (clas == Z_CLASS_COOKIE) {
-+        if (s->lookahead) {
-+            /* Alternative class data must always be presented at the beginning
-+             * of a block. */
-+            return Z_BUF_ERROR;
-+        }
-+        input_length = s->strm->avail_in;
-+    }
- 
-     /* Process the input block. */
-     for (;;) {
-@@ -1648,13 +1821,18 @@ local block_state deflate_slow(s, flush)
-         s->prev_length = s->match_length, s->prev_match = s->match_start;
-         s->match_length = MIN_MATCH-1;
- 
--        if (hash_head != NIL && s->prev_length < s->max_lazy_match &&
--            s->strstart - hash_head <= MAX_DIST(s)) {
-+        if (clas == Z_CLASS_COOKIE && first) {
-+            s->match_length = cookie_match(s, s->strstart, input_length);
-+        } else if (clas == Z_CLASS_STANDARD &&
-+                   hash_head != NIL &&
-+                   s->prev_length < s->max_lazy_match &&
-+                   s->strstart - hash_head <= MAX_DIST(s)) {
-             /* To simplify the code, we prevent matches with the string
-              * of window index 0 (in particular we have to avoid a match
-              * of the string with itself at the start of the input file).
-              */
--            s->match_length = longest_match (s, hash_head);
-+            s->match_length = longest_match (s, hash_head, clas);
-+
-             /* longest_match() sets match_start */
- 
-             if (s->match_length <= 5 && (s->strategy == Z_FILTERED
-@@ -1673,7 +1851,22 @@ local block_state deflate_slow(s, flush)
-         /* If there was a match at the previous step and the current
-          * match is not better, output the previous match:
-          */
--        if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) {
-+        first = 0;
-+        if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length &&
-+            /* We will only accept an exact match for Z_CLASS_COOKIE data and
-+             * we won't match Z_CLASS_HUFFMAN_ONLY data at all. */
-+            (clas == Z_CLASS_STANDARD || (clas == Z_CLASS_COOKIE &&
-+                            s->prev_length == input_length &&
-+                            s->prev_match > 0 &&
-+                            /* We require that a Z_CLASS_COOKIE match be
-+                             * preceded by either a semicolon (which cannot be
-+                             * part of a cookie), or non-cookie data. This is
-+                             * to prevent
-+                             * a cookie from being a prefix of another.
-+                             * spdy_framer.cc ensures that cookies are always
-+                             * terminated by a semicolon. */
-+                            (class_at(s, s->prev_match-1) == Z_CLASS_STANDARD ||
-+                             *(s->window + s->prev_match-1) == ';')))) {
-             uInt max_insert = s->strstart + s->lookahead - MIN_MATCH;
-             /* Do not insert strings in hash table beyond this. */
- 
-diff --git a/third_party/zlib/deflate.h b/third_party/zlib/deflate.h
-index cbf0d1e..83b4602 100644
---- a/third_party/zlib/deflate.h
-+++ b/third_party/zlib/deflate.h
-@@ -91,6 +91,9 @@ typedef unsigned IPos;
-  * save space in the various tables. IPos is used only for parameter passing.
-  */
- 
-+#define Z_COOKIE_HASH_SIZE 64
-+#define Z_COOKIE_HASH_MASK (Z_COOKIE_HASH_SIZE-1)
-+
- typedef struct internal_state {
-     z_streamp strm;      /* pointer back to this zlib stream */
-     int   status;        /* as the name implies */
-@@ -139,6 +142,8 @@ typedef struct internal_state {
-     uInt  hash_mask;      /* hash_size-1 */
- 
-     uInt  hash_shift;
-+    Bytef *class_bitmap;  /* bitmap of class for each byte in window */
-+    IPos cookie_locations[Z_COOKIE_HASH_SIZE];
-     /* Number of bits by which ins_h must be shifted at each input
-      * step. It must be such that after MIN_MATCH steps, the oldest
-      * byte no longer takes part in the hash key, that is:
-diff --git a/third_party/zlib/zlib.h b/third_party/zlib/zlib.h
-index 4d54af9..929f7b4 100644
---- a/third_party/zlib/zlib.h
-+++ b/third_party/zlib/zlib.h
-@@ -101,6 +101,7 @@ typedef struct z_stream_s {
-     int     data_type;  /* best guess about the data type: binary or text */
-     uLong   adler;      /* adler32 value of the uncompressed data */
-     uLong   reserved;   /* reserved for future use */
-+    int     clas;
- } z_stream;
- 
- typedef z_stream FAR *z_streamp;
-@@ -207,6 +208,10 @@ typedef gz_header FAR *gz_headerp;
- 
- #define Z_NULL  0  /* for initializing zalloc, zfree, opaque */
- 
-+#define Z_CLASS_STANDARD 0
-+#define Z_CLASS_COOKIE 1
-+#define Z_CLASS_HUFFMAN_ONLY 2
-+
- #define zlib_version zlibVersion()
- /* for compatibility with versions < 1.0.2 */
- 
diff --git a/third_party/zlib/zlib.gyp b/third_party/zlib/zlib.gyp
index d856897..5e4c200 100644
--- a/third_party/zlib/zlib.gyp
+++ b/third_party/zlib/zlib.gyp
@@ -5,12 +5,12 @@
 {
   'variables': {
     'conditions': [
-      [ 'OS=="none"', {
-        # Because we have a patched zlib, we cannot use the system libz.
+      [ 'os_posix == 1 and OS != "mac" and OS != "ios" and OS != "openbsd"', {
+        # Link to system .so since we already use it due to GTK.
         # TODO(pvalchev): OpenBSD is purposefully left out, as the system
         # zlib brings up an incompatibility that breaks rendering.
         'use_system_zlib%': 1,
-      }, {
+      }, {  # os_posix != 1 or OS == "mac" or OS == "ios" or OS == "openbsd"
         'use_system_zlib%': 0,
       }],
     ],
@@ -70,8 +70,6 @@
               'sources!': [
                 'contrib/minizip/iowin32.c'
               ],
-            }], ['OS=="android"', {
-              'toolsets': ['target', 'host'],
             }],
           ],
         }, {
diff --git a/third_party/zlib/zlib.h b/third_party/zlib/zlib.h
index 929f7b4..4d54af9 100644
--- a/third_party/zlib/zlib.h
+++ b/third_party/zlib/zlib.h
@@ -101,7 +101,6 @@ typedef struct z_stream_s {
     int     data_type;  /* best guess about the data type: binary or text */
     uLong   adler;      /* adler32 value of the uncompressed data */
     uLong   reserved;   /* reserved for future use */
-    int     clas;
 } z_stream;
 
 typedef z_stream FAR *z_streamp;
@@ -208,10 +207,6 @@ typedef gz_header FAR *gz_headerp;
 
 #define Z_NULL  0  /* for initializing zalloc, zfree, opaque */
 
-#define Z_CLASS_STANDARD 0
-#define Z_CLASS_COOKIE 1
-#define Z_CLASS_HUFFMAN_ONLY 2
-
 #define zlib_version zlibVersion()
 /* for compatibility with versions < 1.0.2 */