DevTools: Fix build target dependencies following r182595

BUG=391566
TBR=pfeldman

Review URL: https://codereview.chromium.org/602753002

git-svn-id: svn://svn.chromium.org/blink/trunk@182619 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: properly inject elements panel context menu items.

BUG=417275

Review URL: https://codereview.chromium.org/603643002

git-svn-id: svn://svn.chromium.org/blink/trunk@182620 bbb929c8-8fbe-4397-9dbb-9b2b20218538