Revert of Use Stub CDM for building libwidevinecdmadapter.so (patchset #4 id:100001 of https://codereview.chromium.org/2792743002/ )

Reason for revert:
Using stub cdm is a workaround and it breaks the load_library_perf_test.
This change reverts the stub cdm because the unaligned ELF header issue
has been fixed for libwidevinecdm.so, so that we can re-enable the
load_library_perf_test.

Original issue's description:
> Use Stub CDM for building libwidevinecdmadapter.so
>
> - This is a temporary fix for unblocking LLD.
> - We use the stub CDM to build the CDM adapter.
> - We ship the copied (real) CDM and the CDM adapter.
> - Even though the CDM adapter is built against the stub cdm at
>   "stub_cdm/libwidevinecdm.so", only the filename is baked
>   into the adapter because of the gn dependency,
>   e.g., readelf -d libwidevinecdmadapter.so :
>   0x0000000000000001 (NEEDED)    Shared library: [libwidevinecdm.so]
> - At run time, when loading the CDM adapter, the system will search
>   for the CDM in the same dir where the adapter is located. Hence
>   the real CDM will be loaded.
>
> BUG=707488
>
> Review-Url: https://codereview.chromium.org/2792743002
> Cr-Commit-Position: refs/heads/master@{#462104}
> Committed: https://chromium.googlesource.com/chromium/src/+/4bd7678fefa459f3f29a4ea511ff26971cfb5648

TBR=xhwang@chromium.org,hmchen@google.com
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=707488

Review-Url: https://codereview.chromium.org/2893853003
Cr-Commit-Position: refs/heads/master@{#473408}
1 file changed