Reland of "Fix build of Widevine CDM stub on Mac"

The combination of 'branding=Chromium' and 'enable_widevine=1' causes
'widevinecdm' to be a 'shared_library' build of the CDM stub.
Additionally combined with 'mac_strip_release=1', this triggers
'strip_save_dsym', which fails, because it doesn't support
'product_dir'.

This fix does to 'widevinecdm' what has already been done to
'clearkeycdm': Split the target into 'widevinecdm_binary' which builds
and strips the stub binary, and 'widevinecdm' which just copies the
binary.

This CL relands https://codereview.chromium.org/2117343005/ with the
following change:

The new 'widevinecdm_binary' target is now defined conditionally for the
case when it is really needed, to fix the ninja error "multiple rules
generate WidevineCdm/_platform_specific/win_x86/widevinecdm.dll".

BUG=622282

TEST='build/gyp_chromium -Gconfig=Release -Dbranding=Chromium -Denable_widevine=1 -Dmac_strip_release=1 && ninja -C out/Release widevinecdm' is successful

Review-Url: https://codereview.chromium.org/2149233003
Cr-Commit-Position: refs/heads/master@{#405635}
1 file changed