Add call accessibility activity.

This pulls accessibility settings (which are not SIM-dependent) from
CallFeaturesSettings to their own Activity.

+ Added Accessibility settings activity and fragment.
+ Moved logic from CallFeatureSettings to new activity.
+ Defined a new file for constants pertaining to settings.

Bug: 19372734
Change-Id: I12d03c6c97c4573641c075a856dcc68260a579b8
diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index 3be2bb0..b165ab1 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -440,6 +440,17 @@
             </intent-filter>
         </receiver>
 
+        <!-- "Accessibility" settings UI. Referenced by Dialer application. -->
+        <activity android:name="com.android.phone.settings.AccessibilitySettingsActivity"
+                android:label="@string/accessibility_settings_activity_title"
+                android:theme="@style/DialerSettingsLight">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <action android:name="android.telecom.action.SHOW_CALL_ACCESSIBILITY_SETTINGS" />
+                <category android:name="android.intent.category.DEFAULT" />
+            </intent-filter>
+        </activity>
+
         <!-- CDMA Emergency Callback Mode -->
         <service android:name="EmergencyCallbackModeService">
         </service>