Update cookie value and attribute setting behavior to match other UAs

net/cookies/parsed_cookie.cc

Index: net/cookies/parsed_cookie.cc
diff --git a/net/cookies/parsed_cookie.cc b/net/cookies/parsed_cookie.cc
index 2175692f534a0ff8c4db3a65f898858a47da8a10..0be70e1565fec6579c369ef13c5dc3d0dd83b4f5 100644
--- a/net/cookies/parsed_cookie.cc
+++ b/net/cookies/parsed_cookie.cc
@@ -195,7 +195,7 @@ CookiePriority ParsedCookie::Priority() const {
 }
 
 bool ParsedCookie::SetName(const std::string& name) {
-  if (!IsValidToken(name))
+  if (!name.empty() && !IsValidToken(name))
     return false;
   if (pairs_.empty())
     pairs_.push_back(std::make_pair("", ""));
@@ -363,12 +363,26 @@ void ParsedCookie::ParseTokenValuePairs(const std::string& cookie_line) {
   // Then we can log any unexpected terminators.
   std::string::const_iterator end = FindFirstTerminator(cookie_line);
 
+  // For an empty |cookie_line|, add an empty-key with an empty value, which
+  // has the effect of clearing any prior setting of the empty-key. This is done
+  // to match the behavior of other browsers. See https://crbug.com/601786.
+  if (it == end) {
+    pairs_.push_back(TokenValuePair("", ""));
+    return;
+  }
+
   for (int pair_num = 0; pair_num < kMaxPairs && it != end; ++pair_num) {
     TokenValuePair pair;
 
     std::string::const_iterator token_start, token_end;
-    if (!ParseToken(&it, end, &token_start, &token_end))
-      break;
+    if (!ParseToken(&it, end, &token_start, &token_end)) {
+      // Allow first token to be treated as empty-key if unparsable
+      if (pair_num != 0)
+        break;
+
+      // If parsing failed, start the value parsing at the very beginning.
+      token_start = start;
+    }
 
     if (it == end || *it != '=') {
       // We have a token-value, we didn't have any token name.
@@ -421,17 +435,11 @@ void ParsedCookie::ParseTokenValuePairs(const std::string& cookie_line) {
 }
 
 void ParsedCookie::SetupAttributes() {
-  // Ignore Set-Cookie directive where name and value are both empty.
-  if (pairs_[0].first.empty() && pairs_[0].second.empty()) {
-    pairs_.clear();
-    return;
-  }
-
   // We skip over the first token/value, the user supplied one.
   for (size_t i = 1; i < pairs_.size(); ++i) {
     if (pairs_[i].first == kPathTokenName) {
       path_index_ = i;
-    } else if (pairs_[i].first == kDomainTokenName) {
+    } else if (pairs_[i].first == kDomainTokenName && pairs_[i].second != "") {
       domain_index_ = i;
     } else if (pairs_[i].first == kExpiresTokenName) {
       expires_index_ = i;