Consistent fading behavior for touch editing handles

The general rule is that touch editing handles should fade out when they
are dismissed, unless handles and text are moving relative to each
other. So, handles fade out except in following cases, in which they
disappear almost immediately (i.e. they fade out super quickly):
- When handle is dragged out of content view. In this case it should
  actually scroll the contents, but that's a separate issue (see
  crbug.com/269003);
- When starting touch scrolling or gesture navigation.

BUG=313561

Review URL: https://codereview.chromium.org/138033014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@245610 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 245610