Add packages/providers/BookmarkProvider

BookmarkProvider will be the provider code from the legacy browser, refactored
into its own app. It will fill the role of Browser provider when Clank is
unavailable (such as on emulation) so we can remove the legacy browser.

BUG:19682629
diff --git a/default.xml b/default.xml
index ad028bd..b80592d 100644
--- a/default.xml
+++ b/default.xml
@@ -409,6 +409,7 @@
   <project path="packages/inputmethods/LatinIME" name="platform/packages/inputmethods/LatinIME" />
   <project path="packages/inputmethods/OpenWnn" name="platform/packages/inputmethods/OpenWnn" />
   <project path="packages/providers/ApplicationsProvider" name="platform/packages/providers/ApplicationsProvider" />
+  <project path="packages/providers/BookmarkProvider" name="platform/packages/providers/BookmarkProvider" />
   <project path="packages/providers/CalendarProvider" name="platform/packages/providers/CalendarProvider" groups="pdk-cw-fs" />
   <project path="packages/providers/ContactsProvider" name="platform/packages/providers/ContactsProvider" groups="pdk-cw-fs" />
   <project path="packages/providers/DownloadProvider" name="platform/packages/providers/DownloadProvider" groups="pdk-cw-fs" />