Defer to generate breakpad symbols to decide whether or not to dump symbols

When using shared libraries, the main binary might not have been touched
even if one of the dependencies was updated.

BUG=369608
R=dpranke@chromium.org

Review URL: https://codereview.chromium.org/276433002

git-svn-id: svn://svn.chromium.org/blink/trunk@173544 bbb929c8-8fbe-4397-9dbb-9b2b20218538