Move libvpx from DEPS to src

third_party/libvpx/source/libvpx/.gitignore

Index: third_party/libvpx/source/libvpx/.gitignore
diff --git a/third_party/libvpx/source/libvpx/.gitignore b/third_party/libvpx/source/libvpx/.gitignore
new file mode 100644
index 0000000000000000000000000000000000000000..dce4cfabacdba8784d9adbb0c437a37e66abe149
--- /dev/null
+++ b/third_party/libvpx/source/libvpx/.gitignore
@@ -0,0 +1,60 @@
+*.S
+*.a
+*.asm.s
+*.d
+*.gcda
+*.gcno
+*.o
+*~
+.cproject
+.project
+.settings
+/*-*.mk
+/*.asm
+/*.doxy
+/*.ivf
+/*.ivf.md5
+/.bins
+/.deps
+/.docs
+/.install-*
+/.libs
+/Makefile
+/config.log
+/config.mk
+/docs/
+/doxyfile
+/examples/*.dox
+/examples/decode_to_md5
+/examples/decode_with_drops
+/examples/decode_with_partial_drops
+/examples/example_xma
+/examples/postproc
+/examples/set_maps
+/examples/simple_decoder
+/examples/simple_encoder
+/examples/twopass_encoder
+/examples/vp8_multi_resolution_encoder
+/examples/vp8cx_set_ref
+/examples/vp9_spatial_scalable_encoder
+/examples/vpx_temporal_scalable_patterns
+/ivfdec
+/ivfdec.dox
+/ivfenc
+/ivfenc.dox
+/libvpx.so*
+/libvpx.ver
+/samples.dox
+/test_libvpx
+/vp8_api1_migration.dox
+/vp[89x]_rtcd.h
+/vpx.pc
+/vpx_config.c
+/vpx_config.h
+/vpx_scale_rtcd.h
+/vpx_version.h
+/vpxdec
+/vpxdec.dox
+/vpxenc
+/vpxenc.dox
+TAGS