Add config change handling to SourceBufferStream & ChunkDemuxer

media/base/video_decoder_config.cc

Index: media/base/video_decoder_config.cc
diff --git a/media/base/video_decoder_config.cc b/media/base/video_decoder_config.cc
index 1a1783d1c0d758fbc6a7c16bab5e4cc7fe27eb3f..1e00e34c3f71a7617323673d38955dda48c7d42c 100644
--- a/media/base/video_decoder_config.cc
+++ b/media/base/video_decoder_config.cc
@@ -149,6 +149,18 @@ bool VideoDecoderConfig::IsValidConfig() const {
           format_, natural_size_.width(), natural_size_.height());
 }
 
+bool VideoDecoderConfig::Matches(const VideoDecoderConfig& config) const {
+  return ((codec() == config.codec()) &&
+          (format() == config.format()) &&
+          (profile() == config.profile()) &&
+          (coded_size() == config.coded_size()) &&
+          (visible_rect() == config.visible_rect()) &&
+          (natural_size() == config.natural_size()) &&
+          (extra_data_size() == config.extra_data_size()) &&
+          (!extra_data() || !memcmp(extra_data(), config.extra_data(),
+                                    extra_data_size())));
+}
+
 std::string VideoDecoderConfig::AsHumanReadableString() const {
   std::ostringstream s;
   s << "codec: " << codec()