Show the saved picture for freed tabs.

Show the saved picture for freed tabs.

Create a small class containing the data needed to display the saved or current
picture. For freed tabs, inflate the picture and use the saved state from
mSavedState. Reorganize populatePickerData to use the current top window or the
saved state depending on if the tab has been freed.

There was another bug where onNewPicture would update the wrong FakeWebView due
to ListViews reusing the same view. Have the tab manage the new picture and
invalidate the FakeWebView. When reusing the view, clear out the tab's
FakeWebView field.

Wipe all the picker data at the same time the ImageGrid and ImageAdapter are
cleared.