Rename DemuxerStreamProvider into MediaResource

Review-Url: https://codereview.chromium.org/2668393002
Cr-Commit-Position: refs/heads/master@{#447700}

• chromecast/media/service/cast_renderer.cc[diff]
• chromecast/media/service/cast_renderer.h[diff]
• content/browser/media/android/media_player_renderer.cc[diff]
• content/browser/media/android/media_player_renderer.h[diff]
• content/renderer/media/android/media_player_renderer_client.cc[diff]
• content/renderer/media/android/media_player_renderer_client.h[diff]
• media/base/BUILD.gn[diff]
• media/base/demuxer.h[diff]
• media/base/demuxer_stream_provider.cc[Deleted - diff]
• media/base/fake_demuxer_stream.cc[diff]
• media/base/fake_demuxer_stream.h[diff]
• media/base/media_resource.cc[Added - diff]
• media/base/media_resource.h[Renamed from media/base/demuxer_stream_provider.h - diff]
• media/base/media_url_demuxer.cc[diff]
• media/base/media_url_demuxer.h[diff]
• media/base/media_url_demuxer_unittest.cc[diff]
• media/base/mock_filters.h[diff]
• media/base/pipeline_impl.cc[diff]
• media/base/renderer.h[diff]
• media/mojo/clients/mojo_renderer.cc[diff]
• media/mojo/clients/mojo_renderer.h[diff]
• media/mojo/services/BUILD.gn[diff]
• media/mojo/services/media_resource_shim.cc[Renamed from media/mojo/services/demuxer_stream_provider_shim.cc - diff]
• media/mojo/services/media_resource_shim.h[Renamed from media/mojo/services/demuxer_stream_provider_shim.h - diff]
• media/mojo/services/mojo_renderer_service.cc[diff]
• media/mojo/services/mojo_renderer_service.h[diff]
• media/remoting/BUILD.gn[diff]
• media/remoting/courier_renderer.cc[diff]
• media/remoting/courier_renderer.h[diff]
• media/remoting/courier_renderer_unittest.cc[diff]
• media/remoting/demuxer_stream_adapter_unittest.cc[diff]
• media/remoting/fake_media_resource.cc[Renamed from media/remoting/fake_demuxer_stream_provider.cc - diff]
• media/remoting/fake_media_resource.h[Renamed from media/remoting/fake_demuxer_stream_provider.h - diff]
• media/renderers/renderer_impl.cc[diff]
• media/renderers/renderer_impl.h[diff]
• media/renderers/renderer_impl_unittest.cc[diff]