Remove pthreads patch, roll in new patches, disable unchecked bit readers.

chromium/patches/to_upstream/54_mov_stss.patch

Index: chromium/patches/to_upstream/54_mov_stss.patch
diff --git a/chromium/patches/to_upstream/54_mov_stss.patch b/chromium/patches/to_upstream/54_mov_stss.patch
new file mode 100644
index 0000000000000000000000000000000000000000..1325b483064ddfd0a7f5a9c476751abd47f511db
--- /dev/null
+++ b/chromium/patches/to_upstream/54_mov_stss.patch
@@ -0,0 +1,12 @@
+diff -wurp -N orig/libavformat/mov.c ffmpeg/libavformat/mov.c
+--- orig/libavformat/mov.c	2012-02-03 11:39:21.961119253 -0800
++++ ffmpeg/libavformat/mov.c	2012-02-03 11:39:56.500485313 -0800
+@@ -1558,7 +1558,7 @@ static void mov_build_index(MOVContext *
+         unsigned int stts_sample = 0;
+         unsigned int sample_size;
+         unsigned int distance = 0;
+-        int key_off = sc->keyframes && sc->keyframes[0] == 1;
++        int key_off = sc->keyframe_count && sc->keyframes[0] == 1;
+ 
+         current_dts -= sc->dts_shift;
+