Only allow extension pages to be displayed in the sidebar to be consistent
with the rest of the extension system.

Change extension manifest "sidebar" section and sidebar API accordingly:

"sidebar": {
  "default_icon": "",
  "default_page": "",
  "default_title": ""
}

chrome.experimental.sidebar.navigate({tabId: ..., path: ...})

BUG=51084
TEST=browser_tests::Sidebar.*, unit_tests::ExtensionManifestTest.Sidebar

Review URL: http://codereview.chromium.org/6378009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@72514 0039d316-1c4b-4281-b951-d872f2087c98
26 files changed