The ScriptBreakpoint struct was before just holding line, column and
condition. It now additionally holds the scriptId.
This encapsulates information nicer, and allows for easier translation
of wasm locations, since one struct now holds all information needed
for the translation.

BUG=chromium:659715
R=yangguo@chromium.org, kozyatinskiy@chromium.org

Review-Url: https://codereview.chromium.org/2491133003
Cr-Commit-Position: refs/heads/master@{#41044}