WebUI: Remove unnecessary preprocessor includes from icon.js.
WebUI: Remove unnecessary preprocessor includes from icon.js.

<include> comments cause the preprocessor to inline the dependencies,
which resulted in duplicated code, since the dependencies are already
included via a <script> or HTML import.

CQ_INCLUDE_TRYBOTS=tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/1964143003
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#392795}

axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk