File descriptor leak on PRINT_UNSYMBOLIZED_STACK_TRACES mode

When PRINT_UNSYMBOLIZED_STACK_TRACES is on, |object_fd| is created in
|SymbolizeAndDemangle| but not used. The handle is not closed when
returning the function.

This CL fixes this file descriptor leak by using FileDescriptor.

Change-Id: I216c00690946671edd802f91fd694573d5783ba0
Reviewed-on: https://chromium-review.googlesource.com/1120087
Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Hajime Hoshi <hajimehoshi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#574087}

base/third_party/symbolize/symbolize.cc

@@ -778,8 +778,11 @@ static ATTRIBUTE_NOINLINE bool SymbolizeAndDemangle(void *pc, char *out,
                                                              out_size - 1);
   }
 
+#if defined(PRINT_UNSYMBOLIZED_STACK_TRACES)
+  {
+    FileDescriptor wrapped_object_fd(object_fd);
+#else
   // Check whether a file name was returned.
-#if !defined(PRINT_UNSYMBOLIZED_STACK_TRACES)
   if (object_fd < 0) {
 #endif
     if (out[1]) {
@@ -795,9 +798,7 @@ static ATTRIBUTE_NOINLINE bool SymbolizeAndDemangle(void *pc, char *out,
     }
     // Failed to determine the object file containing PC.  Bail out.
     return false;
-#if !defined(PRINT_UNSYMBOLIZED_STACK_TRACES)
   }
-#endif
   FileDescriptor wrapped_object_fd(object_fd);
   int elf_type = FileGetElfType(wrapped_object_fd.get());
   if (elf_type == -1) {