API Review cleanups.

- New @SystemApis on Conference and PhoneAccount were missing the required
permissions annotations.
- Rename PROPERTY_ASSISTED_DIALING_USED to PROPERTY_ASSISTED_DIALING
- Standardize get/setConnectionStartElapsedRealtimeMillis method naming
across Connection and Conference classes.
- Clarify Conference#sendConferenceEvent API documentation to match the
docs present for similar method in Connection; include some examples of
valid event/extras combinations.
- Update TelecomManager#getDefaultdialerPackage to use UserHandle instead
of userId.
- Move Conference#getConnectionStartElapsedRealtimeMillis to public API
since the setter is already part of the public API.

Test: Run Telecom and Telephony CTS tests.
Test: Run Telephony unit tests.
Test: Perform manual single-party-conference regression test to confirm
that conference behavior does not regress.

Bug: 147301297
Bug: 148286830
Bug: 148284863
Bug: 148284843
Bug: 148287068
Bug: 148285484
Bug: 148285560
Change-Id: I1f446d81859fa109d74af3661a42a0bd224de5aa
Merged-In: I1f446d81859fa109d74af3661a42a0bd224de5aa
diff --git a/telecomm/java/android/telecom/Call.java b/telecomm/java/android/telecom/Call.java
index f54f8d1..005fcac 100644
--- a/telecomm/java/android/telecom/Call.java
+++ b/telecomm/java/android/telecom/Call.java
@@ -539,7 +539,7 @@
          *
          * @see TelecomManager#EXTRA_USE_ASSISTED_DIALING
          */
-        public static final int PROPERTY_ASSISTED_DIALING_USED = 0x00000200;
+        public static final int PROPERTY_ASSISTED_DIALING = 0x00000200;
 
         /**
          * Indicates that the call is an RTT call. Use {@link #getRttCall()} to get the
@@ -743,7 +743,7 @@
             if (hasProperty(properties, PROPERTY_HAS_CDMA_VOICE_PRIVACY)) {
                 builder.append(" PROPERTY_HAS_CDMA_VOICE_PRIVACY");
             }
-            if (hasProperty(properties, PROPERTY_ASSISTED_DIALING_USED)) {
+            if (hasProperty(properties, PROPERTY_ASSISTED_DIALING)) {
                 builder.append(" PROPERTY_ASSISTED_DIALING_USED");
             }
             if (hasProperty(properties, PROPERTY_NETWORK_IDENTIFIED_EMERGENCY_CALL)) {