[Cronet] Expose quic_user_agent_id and quic_prefer_aes config options.

components/cronet/android/api/src/org/chromium/net/CronetEngine.java

Index: components/cronet/android/api/src/org/chromium/net/CronetEngine.java
diff --git a/components/cronet/android/api/src/org/chromium/net/CronetEngine.java b/components/cronet/android/api/src/org/chromium/net/CronetEngine.java
index a07ae3cc9248805605176b6d23c92ecf1ac82bdf..2e2abe3e68a4105190b265f67cd0d3668c1d09bf 100644
--- a/components/cronet/android/api/src/org/chromium/net/CronetEngine.java
+++ b/components/cronet/android/api/src/org/chromium/net/CronetEngine.java
@@ -104,6 +104,7 @@ public abstract class CronetEngine {
         private LibraryLoader mLibraryLoader;
         private String mLibraryName;
         private boolean mQuicEnabled;
+        private String mQuicUserAgentId;
         private boolean mHttp2Enabled;
         private boolean mSdchEnabled;
         private String mDataReductionProxyKey;
@@ -131,8 +132,8 @@ public abstract class CronetEngine {
         }
 
         /**
-         * Constructs a User-Agent string including Cronet version, and
-         * application name and version.
+         * Constructs a User-Agent string including application name and version,
+         * system build version, model and id, and Cronet version.
          *
          * @return User-Agent string.
          */
@@ -254,6 +255,29 @@ public abstract class CronetEngine {
         }
 
         /**
+         * Constructs default QUIC User Agent Id string including application name
+         * and Cronet version.
+         *
+         * @return QUIC User Agent ID string.
+         */
+        public String getDefaultQuicUserAgentId() {

[xunjieli, 2016/02/04 14:00:06]

I feel that since we are in experimental stage here, we should avoid adding more
public APIs, which likely will be removed when QUIC in Cronet matures. Should we
consider passing the values using setExperimentalOptions? That way it is more
flexible in case we want to remove anything. Also will client be setting the UIC
User Agent themselves? If not, we can just use the default string.

+            return UserAgent.getQuicUserAgentIdFrom(mContext);
+        }
+
+        /**
+         * Overrides the UIC User Agent Id for all requests.
+         * @return the builder to facilitate chaining.
+         */
+        public Builder setQuicUserAgentId(String quicUserAgentId) {
+            mQuicUserAgentId = quicUserAgentId;
+            return this;
+        }
+
+        String getQuicUserAgentId() {
+            return mQuicUserAgentId;
+        }
+
+        /**
          * Sets whether <a href="https://tools.ietf.org/html/rfc7540">HTTP/2</a>
          * protocol is enabled. Defaults to enabled.
          * @param value {@code true} to enable HTTP/2, {@code false} to disable.
@@ -911,6 +935,9 @@ public abstract class CronetEngine {
         if (builder.getUserAgent() == null) {
             builder.setUserAgent(builder.getDefaultUserAgent());
         }
+        if (builder.quicEnabled() && builder.getQuicUserAgentId() == null) {
+            builder.setQuicUserAgentId(builder.getQuicUserAgentId());
+        }
         if (!builder.legacyMode()) {
             cronetEngine = createCronetEngine(builder);
         }