WebRtcBrowserTest with VP8 and VP9. WebRtcTestBase::NegotiateCall specifying video codec.

chrome/test/data/webrtc/munge_sdp.js

Index: chrome/test/data/webrtc/munge_sdp.js
diff --git a/chrome/test/data/webrtc/munge_sdp.js b/chrome/test/data/webrtc/munge_sdp.js
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+/**
+ * Copyright 2016 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.
+ */
+
+/**
+ * See |setSdpDefaultCodec|.
+ */
+function setSdpDefaultAudioCodec(sdp, codec) {
+  return setSdpDefaultCodec(sdp, 'audio', codec);
+}
+
+/**
+ * See |setSdpDefaultCodec|.
+ */
+function setSdpDefaultVideoCodec(sdp, codec) {
+  return setSdpDefaultCodec(sdp, 'video', codec);
+}
+
+/**
+ * Returns a modified version of |sdp| where the |codec| has been promoted to be
+ * the default codec, i.e. the codec whose ID is first in the list of codecs on
+ * the 'm=|type|' line, where |type| is 'audio' or 'video'.
+ * @private
+ */
+function setSdpDefaultCodec(sdp, type, codec) {
+  var sdpLines = splitSdpLines(sdp);
+
+  // Find codec ID, e.g. 100 for 'VP8' if 'a=rtpmap:100 VP8/9000'.
+  var codecId = findRtpmapId(sdpLines, codec);
+  if (codecId === null) {
+    failure('sdpPreferCodec', 'Unknown ID for |codec| = \'' + codec + '\'.');
+  }
+
+  // Find 'm=|type|' line, e.g. 'm=video 9 UDP/TLS/RTP/SAVPF 100 101 107 116'.
+  var mLineNo = findLine(sdpLines, 'm=' + type);
+  if (mLineNo === null) {
+    failure('setSdpDefaultCodec',
+             '\'m=' + type + '\' line missing from |sdp|.');
+  }
+
+  // Modify video line to use the desired codec as the default.
+  sdpLines[mLineNo] = setMLineDefaultCodec(sdpLines[mLineNo], codecId);
+  return mergeSdpLines(sdpLines);
+}
+
+/**
+ * See |getSdpDefaultCodec|.
+ */
+function getSdpDefaultAudioCodec(sdp) {
+  return getSdpDefaultCodec(sdp, 'audio');
+}
+
+/**
+ * See |getSdpDefaultCodec|.
+ */
+function getSdpDefaultVideoCodec(sdp) {
+  return getSdpDefaultCodec(sdp, 'video');
+}
+
+/**
+ * Gets the default codec according to the |sdp|, i.e. the name of the codec
+ * whose ID is first in the list of codecs on the 'm=|type|' line, where |type|
+ * is 'audio' or 'video'.
+ * @private
+ */
+function getSdpDefaultCodec(sdp, type) {
+  var sdpLines = splitSdpLines(sdp);
+
+  // Find 'm=|type|' line, e.g. 'm=video 9 UDP/TLS/RTP/SAVPF 100 101 107 116'.
+  var mLineNo = findLine(sdpLines, 'm=' + type);
+  if (mLineNo === null) {
+    failure('getSdpDefaultCodec',
+             '\'m=' + type + '\' line missing from |sdp|.');
+  }
+
+  // The default codec's ID.
+  var defaultCodecId = getMLineDefaultCodec(sdpLines[mLineNo]);
+  if (defaultCodecId === null) {
+    failure('getSdpDefaultCodec',
+             '\'m=' + type + '\' line contains no codecs.');
+  }
+
+  // Find codec name, e.g. 'VP8' for 100 if 'a=rtpmap:100 VP8/9000'.
+  var defaultCodec = findRtpmapCodec(sdpLines, defaultCodecId);
+  if (defaultCodec === null) {
+    failure('getSdpDefaultCodec',
+             'Unknown codec name for default codec ' + defaultCodecId + '.');
+  }
+  return defaultCodec;
+}
+
+/**
+ * Searches through all |sdpLines| for the 'a=rtpmap:' line for the codec of
+ * the specified name, returning its ID as an int if found, or null otherwise.
+ * |codec| is the case-sensitive name of the codec.
+ * For example, if |sdpLines| contains 'a=rtpmap:100 VP8/9000' and |codec| is
+ * 'VP8', this function returns 100.
+ * @private
+ */
+function findRtpmapId(sdpLines, codec) {
+  var lineNo = findRtpmapLine(sdpLines, codec);
+  if (lineNo === null)
+    return null;
+  // Parse <id> from 'a=rtpmap:<id> <codec>/<rate>'.
+  var id = sdpLines[lineNo].substring(9, sdpLines[lineNo].indexOf(' '));
+  return parseInt(id);
+}
+
+/**
+ * Searches through all |sdpLines| for the 'a=rtpmap:' line for the codec of
+ * the specified codec ID, returning its name if found, or null otherwise.
+ * For example, if |sdpLines| contains 'a=rtpmap:100 VP8/9000' and |id| is 100,
+ * this function returns 'VP8'.
+ * @private
+ */
+function findRtpmapCodec(sdpLines, id) {
+  var lineNo = findRtpmapLine(sdpLines, id);
+  if (lineNo === null)
+    return null;
+  // Parse <codec> from 'a=rtpmap:<id> <codec>/<rate>'.
+  var from = sdpLines[lineNo].indexOf(' ');
+  var to = sdpLines[lineNo].indexOf('/', from);
+  if (from === null || to === null || from + 1 >= to)
+    failure('findRtpmapCodec', '');
+  return sdpLines[lineNo].substring(from + 1, to);
+}
+
+/**
+ * Finds the first 'a=rtpmap:' line from |sdpLines| that contains |contains| and
+ * returns its line index, or null if no such line was found. |contains| may be
+ * the codec ID, codec name or bitrate. An 'a=rtpmap:' line looks like this:
+ * 'a=rtpmap:<id> <codec>/<rate>'.
+ */
+function findRtpmapLine(sdpLines, contains) {
+  for (var i = 0; i < sdpLines.length; i++) {
+    // Is 'a=rtpmap:' line containing |contains| string?
+    if (sdpLines[i].startsWith('a=rtpmap:') &&
+        sdpLines[i].indexOf(contains) != -1) {
+      // Expecting pattern 'a=rtpmap:<id> <codec>/<rate>'.
+      var pattern = new RegExp('a=rtpmap:(\\d+) \\w+\\/\\d+');
+      if (!sdpLines[i].match(pattern))
+        failure('findRtpmapLine', 'Unexpected "a=rtpmap:" pattern.');
+      // Return line index.
+      return i;
+    }
+  }
+  return null;
+}
+
+/**
+ * Returns a modified version of |mLine| that has |codecId| first in the list of
+ * codec IDs. For example, setMLineDefaultCodec(
+ *     'm=video 9 UDP/TLS/RTP/SAVPF 100 101 107 116 117 96', 107)
+ * Returns:
+ *     'm=video 9 UDP/TLS/RTP/SAVPF 107 100 101 116 117 96'
+ * @private
+ */
+function setMLineDefaultCodec(mLine, codecId) {
+  var elements = mLine.split(' ');
+
+  // Copy first three elements, codec order starts on fourth.
+  var newLine = elements.slice(0, 3);
+
+  // Put target |codecId| first and copy the rest.
+  newLine.push(codecId);
+  for (var i = 3; i < elements.length; i++) {
+    if (elements[i] != codecId)
+      newLine.push(elements[i]);
+  }
+
+  return newLine.join(' ');
+}
+
+/**
+ * Returns the default codec's ID from the |mLine|, or null if the codec list is
+ * empty. The default codec is the codec whose ID is first in the list of codec
+ * IDs on the |mLine|. For example, getMLineDefaultCodec(
+ *     'm=video 9 UDP/TLS/RTP/SAVPF 100 101 107 116 117 96')
+ * Returns:
+ *     100
+ * @private
+ */
+function getMLineDefaultCodec(mLine) {
+  var elements = mLine.split(' ');
+  if (elements.length < 4)
+    return null;
+  return parseInt(elements[3]);
+}
+
+/** @private */
+function splitSdpLines(sdp) {
+  return sdp.split('\r\n');
+}
+
+/** @private */
+function mergeSdpLines(sdpLines) {
+  return sdpLines.join('\r\n');
+}
+
+/** @private */
+function findLine(lines, startsWith) {
+  for (var i = 0; i < lines.length; i++) {
+    if (lines[i].startsWith(startsWith))
+      return i;
+  }
+  return null;
+}