Eliminate BaseSessionServiceDelegateImpl
PersistentTabRestoreService::Delegate is slated for componentization. However,
it inherits from BaseSessionServiceDelegateImpl, which contains //chrome-level
functionality.
This CL eliminates BaseSessionServiceDelegateImpl, instead having
PersistentTabRestoreService::Delegate and SessionService each inherit directly
from BaseSessionServiceDelegate. The one non-trivial method in
BaseSessionServiceDelegateImpl (ShouldTrackEntry()) is pulled out into a
standalone //chrome-level util function to avoid code duplication between
ChromeTabRestoreServiceClient and SessionService.
BUG=530165
Review URL: https://codereview.chromium.org/
1331173002
Cr-Commit-Position: refs/heads/master@{#348363}