MemorySanitizer: remove msan_unpoison_string() from zygote_main_linux.cc

This function is now available from the sanitizer runtime. No need to keep our
own implementation around.

BUG=123263
TBR=jln@chromium.org
NOTRY=true
TEST=compile

Review URL: https://codereview.chromium.org/289473002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@270127 0039d316-1c4b-4281-b951-d872f2087c98

content/zygote/zygote_main_linux.cc

@@ -181,17 +181,6 @@ static void InitLibcLocaltimeFunctions() {
     g_libc_localtime64_r = g_libc_localtime_r;
 }
 
-#if defined(MEMORY_SANITIZER)
-void msan_unpoison_string(const char *s) {
-  if (!s) return;
-  // Can't call strlen() on an uninitialized string. Instead, unpoison byte by
-  // byte until the string is over.
-  do {
-    __msan_unpoison(s, sizeof(*s));
-  } while(*(s++));
-}
-#endif
-
 // Define localtime_override() function with asm name "localtime", so that all
 // references to localtime() will resolve to this function. Notice that we need
 // to set visibility attribute to "default" to export the symbol, as it is set
@@ -213,7 +202,7 @@ struct tm* localtime_override(const time_t* timep) {
     struct tm* res = g_libc_localtime(timep);
 #if defined(MEMORY_SANITIZER)
     if (res) __msan_unpoison(res, sizeof(*res));
-    if (res->tm_zone) msan_unpoison_string(res->tm_zone);
+    if (res->tm_zone) __msan_unpoison_string(res->tm_zone);
 #endif
     return res;
   }
@@ -237,7 +226,7 @@ struct tm* localtime64_override(const time_t* timep) {
     struct tm* res = g_libc_localtime64(timep);
 #if defined(MEMORY_SANITIZER)
     if (res) __msan_unpoison(res, sizeof(*res));
-    if (res->tm_zone) msan_unpoison_string(res->tm_zone);
+    if (res->tm_zone) __msan_unpoison_string(res->tm_zone);
 #endif
     return res;
   }
@@ -258,7 +247,7 @@ struct tm* localtime_r_override(const time_t* timep, struct tm* result) {
     struct tm* res = g_libc_localtime_r(timep, result);
 #if defined(MEMORY_SANITIZER)
     if (res) __msan_unpoison(res, sizeof(*res));
-    if (res->tm_zone) msan_unpoison_string(res->tm_zone);
+    if (res->tm_zone) __msan_unpoison_string(res->tm_zone);
 #endif
     return res;
   }
@@ -279,7 +268,7 @@ struct tm* localtime64_r_override(const time_t* timep, struct tm* result) {
     struct tm* res = g_libc_localtime64_r(timep, result);
 #if defined(MEMORY_SANITIZER)
     if (res) __msan_unpoison(res, sizeof(*res));
-    if (res->tm_zone) msan_unpoison_string(res->tm_zone);
+    if (res->tm_zone) __msan_unpoison_string(res->tm_zone);
 #endif
     return res;
   }