Fix -Wunused-function error in native_stack_sampler_win.cc

This was breaking Windows Clang builds:

..\..\base\profiler\native_stack_sampler_win.cc(82,6) :
error: unused function 'RewritePointerIfInOriginalStack' [-Werror,-Wunused-function]
void RewritePointerIfInOriginalStack(uintptr_t top, uintptr_t bottom,
     ^

BUG=82385
TBR=wittman

Review URL: https://codereview.chromium.org/1394203003 .

Cr-Commit-Position: refs/heads/master@{#353063}
1 file changed