[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 283 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.
+         * @param options JSON formatted experimental options

[mef, 2015/11/06 18:52:39]

nits: in this file we end param@ comments with period. 
Also may want to restore the @return comment.

[xunjieli, 2015/11/13 22:13:06]

Done.

          */
-        public Builder setExperimentalQuicConnectionOptions(String quicConnectionOptions) {
-            return putString(CronetEngineBuilderList.QUIC_OPTIONS, quicConnectionOptions);
+        public Builder setExperimentalOptions(String options) {
+            return putString(CronetEngineBuilderList.EXPERIMENTAL_OPTIONS, options);

[mef, 2015/11/06 18:52:39]

Given that engine building is slow and rare I think it might be worth it to add
a check that options is valid JSON string by trying to load it into JSONObject.

[xunjieli, 2015/11/13 22:13:06]

Do we add a "throws JSONException" to the method signature? or should we catch
the checked exception and throw a runtime exception?
I am not sure if that necessary. We do have a dcheck in
url_request_context_config.cc to make sure it is a json.

         }
 
         /**
          * 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;
     }
 }