Change minimum DTMF event duration to be 40 milliseconds

webrtc/pc/dtmfsender_unittest.cc

 /*
  *  Copyright 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 312 matching lines @@
 TEST_F(DtmfSenderTest, TryInsertDtmfWhenItDoesNotWork) {
   std::string tones = "3,4";
   int duration = 100;
   int inter_tone_gap = 50;
   provider_->SetCanInsertDtmf(false);
   EXPECT_FALSE(dtmf_->InsertDtmf(tones, duration, inter_tone_gap));
 }
 
 TEST_F(DtmfSenderTest, InsertDtmfWithInvalidDurationOrGap) {
   std::string tones = "3,4";
-  int duration = 100;
+  int duration = 40;
   int inter_tone_gap = 50;
 
   EXPECT_FALSE(dtmf_->InsertDtmf(tones, 6001, inter_tone_gap));
-  EXPECT_FALSE(dtmf_->InsertDtmf(tones, 69, inter_tone_gap));
+  EXPECT_FALSE(dtmf_->InsertDtmf(tones, 39, inter_tone_gap));
   EXPECT_FALSE(dtmf_->InsertDtmf(tones, duration, 49));
 
   EXPECT_TRUE(dtmf_->InsertDtmf(tones, duration, inter_tone_gap));
 }