libvpx: Pull from upstream

source/libvpx/test/webm_video_source.h

Index: source/libvpx/test/webm_video_source.h
diff --git a/source/libvpx/test/webm_video_source.h b/source/libvpx/test/webm_video_source.h
index 11d3d234d36cd74b435abc4bf9bab0427589b09c..650bc52dce0915e7f8273b3074a542ad4caced75 100644
--- a/source/libvpx/test/webm_video_source.h
+++ b/source/libvpx/test/webm_video_source.h
@@ -69,6 +69,18 @@ class WebMVideoSource : public CompressedVideoSource {
     }
   }
 
+  void SeekToNextKeyFrame() {
+    ASSERT_TRUE(vpx_ctx_->file != NULL);
+    do {
+      const int status = webm_read_frame(webm_ctx_, &buf_, &buf_sz_, &buf_sz_);
+      ASSERT_GE(status, 0) << "webm_read_frame failed";
+      ++frame_;
+      if (status == 1) {
+        end_of_file_ = true;
+      }
+    } while (!webm_ctx_->is_key_frame && !end_of_file_);
+  }
+
   virtual const uint8_t *cxdata() const {
     return end_of_file_ ? NULL : buf_;
   }