Don't show entire synced notification backlog when the feature turns on.

When we first turn on Synced Notifications, instead of toasting every
notification, we put them into the notification center and only toast ones
that appear after that.  The user will not have seen this feature before,
and we feel that a gentle introduction is better.

Also, while I am in the same part of the code, I fixed the enabled service
list and the initialized service list to go through the preferences service.
For past code review comments we went around the preferneces service to
save extra calls, but when I read the header file, it specified that *all*
get and set of preferences need to go through the preference service.

BUG=295816

Review URL: https://codereview.chromium.org/26292003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@228636 0039d316-1c4b-4281-b951-d872f2087c98
Update default app first run dialog to match new mocks

+ Remove button replaced with Cancel
+ Description removed from the dialog for security reasons
+ Changed heading and removed title for views

BUG=296393
TEST=manual

Review URL: https://codereview.chromium.org/26466006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@228637 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 228636
Remove the state management for ctrl key from the FileManager class.

Previously, the FileManager class manages the state of whether the ctrl key is
pressed or not for the clear-drive-cache command.
This CL extracts the management into the CommandHandler class.

BUG=267281
TEST=manually

Review URL: https://codereview.chromium.org/26817004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@228638 0039d316-1c4b-4281-b951-d872f2087c98
Add missing proto dependencies to browser_chromeos and browser_extensions gyp targets.

BUG=159366

Review URL: https://codereview.chromium.org/27236002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@228639 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 228638
SVN changes up to revision 228639