[Extensions] Restrict tabs.captureVisibleTab()

Modify the permissions for tabs.captureVisibleTab(). Instead of just
checking for <all_urls> and assuming its safe, do the following:
- If the page is a "normal" web page (e.g., http/https), allow the
  capture if the extension has activeTab granted or <all_urls>.
- If the page is a file page (file:///), allow the capture if the
  extension has file access *and* either of the <all_urls> or
  activeTab permissions.
- If the page is a chrome:// page, allow the capture only if the
  extension has activeTab granted.

Bug: 810220

Change-Id: I1e2f71281e2f331d641ba0e435df10d66d721304
Reviewed-on: https://chromium-review.googlesource.com/981195
Commit-Queue: Devlin <rdevlin.cronin@chromium.org>
Reviewed-by: Karan Bhatia <karandeepb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#548891}
bool PermissionsData::CanExecuteScriptEverywhere(const Extension* extension) {
  if (extension->location() == Manifest::COMPONENT)
    return true;

  const ExtensionsClient::ScriptingWhitelist& whitelist =
      ExtensionsClient::Get()->GetScriptingWhitelist();

  return base::ContainsValue(whitelist, extension->id());
}

bool PermissionsData::CanExecuteScriptEverywhere(const Extension* extension) {
  if (extension->location() == Manifest::COMPONENT)
    return true;

  const ExtensionsClient::ScriptingWhitelist& whitelist =
      ExtensionsClient::Get()->GetScriptingWhitelist();

  return base::ContainsValue(whitelist, extension->id());
}
