Annotate libjingle_peerconnection_java with @Nullable.

Bug: webrtc:8881
Change-Id: Ida2ef6c003567d19529c21629c916ed40e8de3a6
Reviewed-on: https://webrtc-review.googlesource.com/63380
Commit-Queue: Sami Kalliomäki <sakal@webrtc.org>
Reviewed-by: Paulina Hensman <phensman@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22563}

sdk/android/api/org/webrtc/PeerConnection.java

@@ -13,6 +13,7 @@ package org.webrtc;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import javax.annotation.Nullable;
 
 /**
  * Java-land version of the PeerConnection APIs; wraps the C++ API
@@ -202,7 +203,7 @@ public class PeerConnection {
     }
 
     public static class Builder {
-      private final List<String> urls;
+      @Nullable private final List<String> urls;
       private String username = "";
       private String password = "";
       private TlsCertPolicy tlsCertPolicy = TlsCertPolicy.TLS_CERT_POLICY_SECURE;
@@ -253,16 +254,19 @@ public class PeerConnection {
       }
     }
 
+    @Nullable
     @CalledByNative("IceServer")
     List<String> getUrls() {
       return urls;
     }
 
+    @Nullable
     @CalledByNative("IceServer")
     String getUsername() {
       return username;
     }
 
+    @Nullable
     @CalledByNative("IceServer")
     String getPassword() {
       return password;
@@ -273,6 +277,7 @@ public class PeerConnection {
       return tlsCertPolicy;
     }
 
+    @Nullable
     @CalledByNative("IceServer")
     String getHostname() {
       return hostname;
@@ -406,19 +411,19 @@ public class PeerConnection {
     // 3) iceCheckMinInterval defines the minimal interval (equivalently the
     // maximum rate) that overrides the above two intervals when either of them
     // is less.
-    public Integer iceCheckIntervalStrongConnectivityMs;
-    public Integer iceCheckIntervalWeakConnectivityMs;
-    public Integer iceCheckMinInterval;
+    @Nullable public Integer iceCheckIntervalStrongConnectivityMs;
+    @Nullable public Integer iceCheckIntervalWeakConnectivityMs;
+    @Nullable public Integer iceCheckMinInterval;
     // The time period in milliseconds for which a candidate pair must wait for response to
     // connectivitiy checks before it becomes unwritable.
-    public Integer iceUnwritableTimeMs;
+    @Nullable public Integer iceUnwritableTimeMs;
     // The minimum number of connectivity checks that a candidate pair must sent without receiving
     // response before it becomes unwritable.
-    public Integer iceUnwritableMinChecks;
+    @Nullable public Integer iceUnwritableMinChecks;
     // The interval in milliseconds at which STUN candidates will resend STUN binding requests
     // to keep NAT bindings open.
     // The default value in the implementation is used if this field is null.
-    public Integer stunCandidateKeepaliveIntervalMs;
+    @Nullable public Integer stunCandidateKeepaliveIntervalMs;
     public boolean disableIPv6OnWifi;
     // By default, PeerConnection will use a limited number of IPv6 network
     // interfaces, in order to avoid too many ICE candidate pairs being created
@@ -426,7 +431,7 @@ public class PeerConnection {
     //
     // Can be set to Integer.MAX_VALUE to effectively disable the limit.
     public int maxIPv6Networks;
-    public IntervalRange iceRegatherIntervalRange;
+    @Nullable public IntervalRange iceRegatherIntervalRange;
 
     // These values will be overridden by MediaStream constraints if deprecated constraints-based
     // create peerconnection interface is used.
@@ -435,16 +440,16 @@ public class PeerConnection {
     public boolean enableCpuOveruseDetection;
     public boolean enableRtpDataChannel;
     public boolean suspendBelowMinBitrate;
-    public Integer screencastMinBitrate;
-    public Boolean combinedAudioVideoBwe;
-    public Boolean enableDtlsSrtp;
+    @Nullable public Integer screencastMinBitrate;
+    @Nullable public Boolean combinedAudioVideoBwe;
+    @Nullable public Boolean enableDtlsSrtp;
     // Use "Unknown" to represent no preference of adapter types, not the
     // preference of adapters of unknown types.
     public AdapterType networkPreference;
     public SdpSemantics sdpSemantics;
 
     // This is an optional wrapper for the C++ webrtc::TurnCustomizer.
-    public TurnCustomizer turnCustomizer;
+    @Nullable public TurnCustomizer turnCustomizer;
 
     // TODO(deadbeef): Instead of duplicating the defaults here, we should do
     // something to pick up the defaults from C++. The Objective-C equivalent
@@ -561,31 +566,37 @@ public class PeerConnection {
       return presumeWritableWhenFullyRelayed;
     }
 
+    @Nullable
     @CalledByNative("RTCConfiguration")
     Integer getIceCheckIntervalStrongConnectivity() {
       return iceCheckIntervalStrongConnectivityMs;
     }
 
+    @Nullable
     @CalledByNative("RTCConfiguration")
     Integer getIceCheckIntervalWeakConnectivity() {
       return iceCheckIntervalWeakConnectivityMs;
     }
 
+    @Nullable
     @CalledByNative("RTCConfiguration")
     Integer getIceCheckMinInterval() {
       return iceCheckMinInterval;
     }
 
+    @Nullable
     @CalledByNative("RTCConfiguration")
     Integer getIceUnwritableTimeout() {
       return iceUnwritableTimeMs;
     }
 
+    @Nullable
     @CalledByNative("RTCConfiguration")
     Integer getIceUnwritableMinChecks() {
       return iceUnwritableMinChecks;
     }
 
+    @Nullable
     @CalledByNative("RTCConfiguration")
     Integer getStunCandidateKeepaliveInterval() {
       return stunCandidateKeepaliveIntervalMs;
@@ -601,11 +612,13 @@ public class PeerConnection {
       return maxIPv6Networks;
     }
 
+    @Nullable
     @CalledByNative("RTCConfiguration")
     IntervalRange getIceRegatherIntervalRange() {
       return iceRegatherIntervalRange;
     }
 
+    @Nullable
     @CalledByNative("RTCConfiguration")
     TurnCustomizer getTurnCustomizer() {
       return turnCustomizer;
@@ -636,16 +649,19 @@ public class PeerConnection {
       return suspendBelowMinBitrate;
     }
 
+    @Nullable
     @CalledByNative("RTCConfiguration")
     Integer getScreencastMinBitrate() {
       return screencastMinBitrate;
     }
 
+    @Nullable
     @CalledByNative("RTCConfiguration")
     Boolean getCombinedAudioVideoBwe() {
       return combinedAudioVideoBwe;
     }
 
+    @Nullable
     @CalledByNative("RTCConfiguration")
     Boolean getEnableDtlsSrtp() {
       return enableDtlsSrtp;
@@ -923,7 +939,7 @@ public class PeerConnection {
   }
 
   public RtpTransceiver addTransceiver(
-      MediaStreamTrack track, RtpTransceiver.RtpTransceiverInit init) {
+      MediaStreamTrack track, @Nullable RtpTransceiver.RtpTransceiverInit init) {
     if (track == null) {
       throw new NullPointerException("No MediaStreamTrack specified for addTransceiver.");
     }
@@ -943,7 +959,7 @@ public class PeerConnection {
   }
 
   public RtpTransceiver addTransceiver(
-      MediaStreamTrack.MediaType mediaType, RtpTransceiver.RtpTransceiverInit init) {
+      MediaStreamTrack.MediaType mediaType, @Nullable RtpTransceiver.RtpTransceiverInit init) {
     if (mediaType == null) {
       throw new NullPointerException("No MediaType specified for addTransceiver.");
     }
@@ -960,7 +976,7 @@ public class PeerConnection {
 
   // Older, non-standard implementation of getStats.
   @Deprecated
-  public boolean getStats(StatsObserver observer, MediaStreamTrack track) {
+  public boolean getStats(StatsObserver observer, @Nullable MediaStreamTrack track) {
     return nativeOldGetStats(observer, (track == null) ? 0 : track.nativeTrack);
   }