Address Call Streaming API review comments.

1. Make CallStreamingService and StreamingCall SystemApi and hide
2. Add android.permission.BIND_STREAMING_SERVICE
3. Change StreamingCall#DisplayName to CharSequence
4. Hide StreamingCall constructor
5. Fix CallControl#startCallStreaming doc

Bug: 265304561
Test: build; add cts
API-Coverage-Bug: 268061643
Change-Id: I29771cfbf60553eb8325e40b2cd11c5828a445e4
diff --git a/telecomm/java/android/telecom/CallControl.java b/telecomm/java/android/telecom/CallControl.java
index f3c91f6..2135e27 100644
--- a/telecomm/java/android/telecom/CallControl.java
+++ b/telecomm/java/android/telecom/CallControl.java
@@ -197,10 +197,10 @@
      *                 of the requested operation.
      *
      *                 {@link OutcomeReceiver#onResult} will be called if Telecom has successfully
-     *                 rejected the incoming call.
+     *                 started the call streaming.
      *
      *                 {@link OutcomeReceiver#onError} will be called if Telecom has failed to
-     *                 reject the incoming call.  A {@link CallException} will be passed that
+     *                 start the call streaming. A {@link CallException} will be passed that
      *                 details why the operation failed.
      */
     public void startCallStreaming(@CallbackExecutor @NonNull Executor executor,
diff --git a/telecomm/java/android/telecom/CallStreamingService.java b/telecomm/java/android/telecom/CallStreamingService.java
index 7f11128..3f538a7 100644
--- a/telecomm/java/android/telecom/CallStreamingService.java
+++ b/telecomm/java/android/telecom/CallStreamingService.java
@@ -19,6 +19,7 @@
 import android.annotation.IntDef;
 import android.annotation.NonNull;
 import android.annotation.SdkConstant;
+import android.annotation.SystemApi;
 import android.app.Service;
 import android.content.Intent;
 import android.os.Handler;
@@ -38,10 +39,22 @@
 /**
  * This service is implemented by an app that wishes to provide functionality for a general call
  * streaming sender for voip calls.
- *
- * TODO: add doc of how to be the general streaming sender
- *
+ * <p>
+ * Below is an example manifest registration for a {@code CallStreamingService}.
+ * <pre>
+ * {@code
+ * <service android:name=".EgCallStreamingService"
+ *     android:permission="android.permission.BIND_CALL_STREAMING_SERVICE" >
+ *     ...
+ *     <intent-filter>
+ *         <action android:name="android.telecom.CallStreamingService" />
+ *     </intent-filter>
+ * </service>
+ * }
+ * </pre>
+ * @hide
  */
+@SystemApi
 public abstract class CallStreamingService extends Service {
     /**
      * The {@link android.content.Intent} that must be declared as handled by the service.
@@ -122,6 +135,13 @@
     /**
      * Call streaming request reject reason used with
      * {@link CallEventCallback#onCallStreamingFailed(int)} to indicate that telecom is rejecting a
+     * call streaming request due to unknown reason.
+     */
+    public static final int STREAMING_FAILED_UNKNOWN = 0;
+
+    /**
+     * Call streaming request reject reason used with
+     * {@link CallEventCallback#onCallStreamingFailed(int)} to indicate that telecom is rejecting a
      * call streaming request because there's an ongoing streaming call on this device.
      */
     public static final int STREAMING_FAILED_ALREADY_STREAMING = 1;
@@ -149,6 +169,7 @@
      */
     @IntDef(prefix = {"STREAMING_FAILED"},
             value = {
+                    STREAMING_FAILED_UNKNOWN,
                     STREAMING_FAILED_ALREADY_STREAMING,
                     STREAMING_FAILED_NO_SENDER,
                     STREAMING_FAILED_SENDER_BINDING_ERROR
diff --git a/telecomm/java/android/telecom/StreamingCall.java b/telecomm/java/android/telecom/StreamingCall.java
index 4b27dd6..d4f4322 100644
--- a/telecomm/java/android/telecom/StreamingCall.java
+++ b/telecomm/java/android/telecom/StreamingCall.java
@@ -18,6 +18,7 @@
 
 import android.annotation.IntDef;
 import android.annotation.NonNull;
+import android.annotation.SystemApi;
 import android.content.ComponentName;
 import android.net.Uri;
 import android.os.Bundle;
@@ -30,7 +31,10 @@
 /**
  * Represents a voip call requested to stream to another device that the general streaming sender
  * app should present to the receiver.
+ *
+ * @hide
  */
+@SystemApi
 public final class StreamingCall implements Parcelable {
     /**
      * The state of a {@code StreamingCall} when newly created. General streaming sender should
@@ -50,9 +54,12 @@
      */
     public static final int STATE_DISCONNECTED = 3;
 
+    /**
+     * @hide
+     */
     private StreamingCall(@NonNull Parcel in) {
         mComponentName = in.readParcelable(ComponentName.class.getClassLoader());
-        mDisplayName = in.readString16NoHelper();
+        mDisplayName = in.readCharSequence();
         mAddress = in.readParcelable(Uri.class.getClassLoader());
         mExtras = in.readBundle();
         mState = in.readInt();
@@ -79,7 +86,7 @@
     @Override
     public void writeToParcel(@androidx.annotation.NonNull Parcel dest, int flags) {
         dest.writeParcelable(mComponentName, flags);
-        dest.writeString16NoHelper(mDisplayName);
+        dest.writeCharSequence(mDisplayName);
         dest.writeParcelable(mAddress, flags);
         dest.writeBundle(mExtras);
         dest.writeInt(mState);
@@ -98,14 +105,14 @@
     public @interface StreamingCallState {}
 
     private final ComponentName mComponentName;
-    private final String mDisplayName;
+    private final CharSequence mDisplayName;
     private final Uri mAddress;
     private final Bundle mExtras;
     @StreamingCallState
     private int mState;
     private StreamingCallAdapter mAdapter = null;
 
-    public StreamingCall(@NonNull ComponentName componentName, @NonNull String displayName,
+    public StreamingCall(@NonNull ComponentName componentName, @NonNull CharSequence displayName,
             @NonNull Uri address, @NonNull Bundle extras) {
         mComponentName = componentName;
         mDisplayName = displayName;
@@ -137,7 +144,7 @@
      * {@code StreamingCall} to the receiver side.
      */
     @NonNull
-    public String getDisplayName() {
+    public CharSequence getDisplayName() {
         return mDisplayName;
     }