net: handle trailing dots in LastTwoLabels.

net/base/ssl_false_start_blacklist.h

Index: net/base/ssl_false_start_blacklist.h
diff --git a/net/base/ssl_false_start_blacklist.h b/net/base/ssl_false_start_blacklist.h
index 17596308d99bd155a225e7afab2a45ec9d1bf447..a32fb28904735e4fcde2f034ff48f0327551c9eb 100644
--- a/net/base/ssl_false_start_blacklist.h
+++ b/net/base/ssl_false_start_blacklist.h
@@ -5,6 +5,8 @@
 #ifndef NET_BASE_SSL_FALSE_START_BLACKLIST_H_
 #define NET_BASE_SSL_FALSE_START_BLACKLIST_H_
 
+#include <string>
+
 #include "base/basictypes.h"
 #include "net/base/net_api.h"
 
@@ -35,20 +37,27 @@ class SSLFalseStartBlacklist {
     return hash;
   }
 
-  // LastTwoLabels returns a pointer within |host| to the last two labels of
-  // |host|. For example, if |host| is "a.b.c.d" then LastTwoLabels will return
-  // "c.d".
+  // LastTwoLabels returns the last two labels of |host|. For example, if
+  // |host| is "a.b.c.d" then LastTwoLabels will return "c.d".
   //   host: a DNS name in dotted form.
-  //   returns: NULL on error, otherwise a pointer inside |host|.
-  static const char* LastTwoLabels(const char* host) {
+  //   returns: empty string on error, otherwise the last two labels.
+  static std::string LastTwoLabels(const char* host) {
     // See comment in |Hash| for why this function is inline.
     const size_t len = strlen(host);
     if (len == 0)
-      return NULL;
+      return std::string();
 
     unsigned dots_found = 0;
     size_t i;
+
+    // Remove trailing dots.
     for (i = len - 1; i < len; i--) {
+      if (host[i] != '.')
+        break;
+    }
+    const size_t end = i;
+
+    for (; i < len; i--) {
       if (host[i] == '.') {
         dots_found++;
         if (dots_found == 2) {
@@ -57,18 +66,18 @@ class SSLFalseStartBlacklist {
         }
       }
     }
-
     if (i > len)
       i = 0;
 
-    if (dots_found == 0)
-      return NULL;  // no names with less than two labels are in the blacklist.
-    if (dots_found == 1) {
+    if (dots_found == 0) {
+      // no names with less than two labels are in the blacklist.
+      return std::string();
+    } else if (dots_found == 1) {
       if (host[0] == '.')
-        return NULL;  // ditto
+        return std::string();  // ditto
     }
 
-    return &host[i];
+    return std::string(&host[i], end - i + 1);
   }
 
   // This is the number of buckets in the blacklist hash table. (Must be a