[NaClDocs] Update the building.rst doc for PNaCl.

Talk about how to use both PNaCl and NaCl-gcc.

BUG=https://code.google.com/p/nativeclient/issues/detail?id=3634
NOTRY=true
(just the docs)

Review URL: https://codereview.chromium.org/26062002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@228242 0039d316-1c4b-4281-b951-d872f2087c98
Ignore all updates during batch mode in BookmarkBarBridge.

Batch mode will result in a complete reload of bookmarks
from the model in ExtensiveBookmarkChangesEnded(), so no
need to incrementally update them in this case.

BUG=281562

Review URL: https://codereview.chromium.org/26502002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@228243 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 228243