[Cronet] Replace setExperimentalQuicConnectionOptions with a more general API

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

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.net;
 
 import android.content.Context;
 import android.support.annotation.IntDef;
 import android.util.Log;
 
@@ skipping 296 matching lines @@
                 hint.put(CronetEngineBuilderList.QUIC_HINT_PORT, port);
                 hint.put(CronetEngineBuilderList.QUIC_HINT_ALT_PORT, alternatePort);
                 quicHints.put(hint);
             } catch (JSONException e) {
                 // Intentionally do nothing.
             }
             return this;
         }
 
         /**
-         * Sets experimental QUIC connection options, overwriting any pre-existing
-         * options. List of options is subject to change.
+         * Sets experimental options to be used in Cronet.
          *
-         * @param quicConnectionOptions comma-separated QUIC options (for example
-         * "PACE,IW10") to use if QUIC is enabled.
-         * @return the builder to facilitate chaining.
+         * Experimental options encoded as a string in a JSON format containing
+         * experiments and their corresponding configuration options. The format
+         * is a JSON object with the name of the experiment as the key, and
+         * experiment options as the value. The experiment options for an
+         * experiment is encoded as a JSON object with option name as the key
+         * and option value as the value:
+         *   {"experiment1": {"option1": "option_value1", "option2":
+         *   "option_value2", ...}, "experiment2: {"option3", "option_value3",
+         *   ...}, ...}

[mef, 2015/10/30 17:15:41]

Maybe add an example of how existing quicConnectionOptions should convert into
experimentalOptions?

Do I understand correctly that it would be something like:

"{\"QUIC\": {\"connection_options\": \"PACE,IW10\"}}" 

[xunjieli, 2015/10/30 17:44:48]

Done. Yes, that is right.

+         *
+         * @param experimentalOptions experimental options as a JSON formatted
+         *         string
          */
-        public Builder setExperimentalQuicConnectionOptions(String quicConnectionOptions) {
-            return putString(CronetEngineBuilderList.QUIC_OPTIONS, quicConnectionOptions);
+        public Builder setExperimentalOptions(String experimentalOptions) {
+            return putString(CronetEngineBuilderList.EXPERIMENTAL_OPTIONS, experimentalOptions);
         }
 
         /**
          * Sets a native MockCertVerifier for testing.
          */
         Builder setMockCertVerifierForTesting(long mockCertVerifier) {
             return putString(
                     CronetEngineBuilderList.MOCK_CERT_VERIFIER, String.valueOf(mockCertVerifier));
         }
 
@@ skipping 339 matching lines @@
                 cronetEngine = possibleEngine;
             }
         } catch (ClassNotFoundException e) {
             // Leave as null.
         } catch (Exception e) {
             throw new IllegalStateException("Cannot instantiate: " + CRONET_URL_REQUEST_CONTEXT, e);
         }
         return cronetEngine;
     }
 }