Implements "chrome://appcache-internals" based on WebUI API
Redid the "chrome://appcache-internals" page so that the new implementation is:
1- Based on "WebUIController" and similar to "chrome://indexed-db-internals".
2- Looks into "all" storage paritions when fetching application cache data.
This was previously reported as a bug since the application cache for <webview>
was not being shown on "chrome://appcache-internals".
BUG=343683
Review URL: https://codereview.chromium.org/
1191383004
Cr-Commit-Position: refs/heads/master@{#342671}