Add user selectable Default Browser feature

- add Default Apps section in Apps / Advanced
- follow UX spec

This change depends on a Framework change which adds new APIs in PackageMaager
for setting and getting the default Browser App package name.

See bug #20144393

Change-Id: I2ff456eeaced9f740f4dd6fb6bccea6de6ea1308

res/values/strings.xml

@@ -5657,6 +5657,7 @@
     <string name="keywords_emergency_app">emergency ice app default</string>
     <string name="keywords_all_apps">apps download applications system</string>
     <string name="keywords_app_permissions">apps permissions security</string>
+    <string name="keywords_default_apps">apps default</string>
     <!-- Search keywords for different screen unlock modes : slide to unlock, password, pattern and PIN [CHAR LIMIT=none] -->
     <string name="keywords_lockscreen">slide password pattern pin</string>
 
@@ -6212,4 +6213,13 @@
         <item quantity="other"><xliff:g id="count" example="10">%d</xliff:g> apps can open their domain URLs</item>
     </plurals>
 
+    <!-- Title for Default Apps settings [CHAR LIMIT=30] -->
+    <string name="default_apps_title">Default Apps</string>
+
+    <!-- Title for Default Browser settings [CHAR LIMIT=30] -->
+    <string name="default_browser_title">Default Browser</string>
+
+    <!-- Summary for No Default Browser settings [CHAR LIMIT=45] -->
+    <string name="default_browser_title_none">No default Browser</string>
+
 </resources>