The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f9d8e609f1298c6a563274fbdbe6ee5c45df3034

commit f9d8e609f1298c6a563274fbdbe6ee5c45df3034
Author: zqzhang <zqzhang@chromium.org>
Date: Mon Dec 05 18:25:42 2016

[MediaElement] Allow preloading for non-network scheme src

This CL weakens the restriction of media element preloading. The
reason for this change is that the preload attribute for media
elements is overriden as "none" when data saver is
enabled. However there is no need to apply this override for
non-network media sources, since they do not cost network
traffic.

BUG= 661220 

Review-Url: https://codereview.chromium.org/2546993003
Cr-Commit-Position: refs/heads/master@{#436358}

[rename] https://crrev.com/f9d8e609f1298c6a563274fbdbe6ee5c45df3034/third_party/WebKit/LayoutTests/http/tests/media/preload-conditions.html
[modify] https://crrev.com/f9d8e609f1298c6a563274fbdbe6ee5c45df3034/third_party/WebKit/Source/core/html/HTMLMediaElement.cpp
[modify] https://crrev.com/f9d8e609f1298c6a563274fbdbe6ee5c45df3034/third_party/WebKit/Source/core/html/HTMLMediaElement.h
[modify] https://crrev.com/f9d8e609f1298c6a563274fbdbe6ee5c45df3034/third_party/WebKit/Source/core/html/HTMLMediaElementTest.cpp

Thanks for fixing!