message: Do not use internal source in video send stream tests.
  Unless testing a behavior specific to video encoders with internal source.
  Cr-Commit-Position: refs/heads/master@{#31740}
diff: @@ -2280,13 +2280,15 @@ TEST_F(VideoSendStreamTest, CanReconfigureToUseStartBitrateAbovePreviousMax) {
  StartBitrateObserver encoder;
  test::VideoEncoderProxyFactory encoder_factory(&encoder);
  - // Since this test does not use a capturer, set |internal_source| = true.
  - // Encoder configuration is otherwise updated on the next video frame.
  - encoder_factory.SetHasInternalSource(true);
  GetVideoSendConfig()->encoder_settings.encoder_factory = &encoder_factory;
  CreateVideoStreams();
  + // Start capturing and encoding frames to force encoder reconfiguration.
  + CreateFrameGeneratorCapturer(kDefaultFramerate, kDefaultWidth,
  + kDefaultHeight);
  + frame_generator_capturer_->Start();
  +
  EXPECT_TRUE(encoder.WaitForStartBitrate());
  EXPECT_EQ(GetVideoEncoderConfig()->max_bitrate_bps / 1000,
  encoder.GetStartBitrateKbps());
  