app_list: One click install for web store result.
- Support one click install from web store search result;
- Support action buttons with a text label in SearchResult;
- Add is_installing and percent_downloaded properties to SearchResult;
- SearchResultView shows blue button for label based action buttons;
- SearchResultView shows progress bar when is_installing is true and use
percent_downloaded for the progress bar;
- Move progress bar drawing code into ProgressBarView to share between
AppListItemView and SearchResultView;
- Move InstallTracker code from webstore private api into WebstoreInstaller
so that the install/download could be observed for both webstore inline
install and WebstoreStandaloneInstaller based install;
BUG=173430
Review URL: https://chromiumcodereview.appspot.com/
17854007
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@208984 0039d316-1c4b-4281-b951-d872f2087c98