Strip top level folders from bookmark search

Bookmarks Bar and Other Bookmarks are the only top level folders in the bookmarks tree, they are not user-created and do not support move/delete functionality.

Including folders in bookmark searches also included the top level folders, and would require extra logic to block move/delete actions on these folders.

Since they are top level, they cannot be collapsed in the bookmark tree on the left pane of the bookmark manager (always visible). Showing them in search results as well can be considered redundant, and removing them from search results avoids extra context menu logic as well as edge cases that were ignored when search was originally restricted to urls and not folders.

Also update search results whenever an item in the search results is cut/deleted/restored.

BUG=324231
BUG=329144

Review URL: https://codereview.chromium.org/102713002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246417 0039d316-1c4b-4281-b951-d872f2087c98
IndexedDB: Only reset prefetch caches for cursors in same transaction

Correct prefetching is predicated on resetting the cache when other
requests come in that could invalidate it (i.e. writes) or result in
requests processing out of order (i.e. everything). When prefetching
was originally implemented, the IDB implementation only handled one
transaction at a time, so resetting was done with a big hammer - reset
all of a front-end's caches when any other request is made. This was
acknowledged as future work during code review.

The future is now! Only reset caches for cursors from the same
transaction as the triggering request, which should be a performance
win for concurrent transactions in the same front-end.

BUG=329950

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=246245

Review URL: https://codereview.chromium.org/128713006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246418 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 246418