DevTools: do not use platform/ to load injected scripts into inspector/v8.

BUG=580337
R=dgozman@chromium.org
TBR=jochen for stray gyp files.
NOTRY=true
(linux_android_rel_ng was sick)

Review URL: https://codereview.chromium.org/1670813003 .

Cr-Commit-Position: refs/heads/master@{#374217}
18 files changed