[PATCH] [Sanitizer] Introduce generic stack frame rendering machinery

[Kostya Serebryany]

LGTM++ with a couple nits.

================
Comment at: lib/sanitizer_common/sanitizer_stacktrace_printer.cc:26
@@ +25,3 @@
+
+const char kDefaultFormat[] = "    #%n %p %F %L";
+
----------------
static

================
Comment at: lib/sanitizer_common/sanitizer_stacktrace_printer.cc:31
@@ +30,3 @@
+                 const char *strip_func_prefix) {
+  if (0 == internal_strcmp(format, "DEFAULT"))
+    format = kDefaultFormat;
----------------
why not nullptr? 

================
Comment at: lib/sanitizer_common/sanitizer_stacktrace_printer.h:10
@@ +9,3 @@
+//
+// This file is shared between AddressSanitizer and ThreadSanitizer
+// run-time libraries.
----------------
..., and other sanitizers

http://reviews.llvm.org/D6140