Don't use -Wl,-z,defs for ubsan builds for now.

Don't use -Wl,-z,defs for ubsan builds for now.

ubsan:
../../third_party/freetype2/src/src/base/ftsystem.c:233:error: undefined reference to '__ubsan_handle_type_mismatch'
../../third_party/freetype2/src/src/base/ftsystem.c:233:error: undefined reference to '__ubsan_handle_type_mismatch'

ubsan_vptr:
../../content/shell/tools/plugin/PluginObject.cpp:1392:error: undefined reference to '__ubsan_vptr_type_cache'
../../content/shell/tools/plugin/PluginObject.cpp:1392:error: undefined reference to '__ubsan_handle_dynamic_type_cache_miss'
../../content/shell/tools/plugin/PluginTest.cpp:61:error: undefined reference to '__ubsan_vptr_type_cache'
../../content/shell/tools/plugin/PluginTest.cpp:61:error: undefined reference to '__ubsan_handle_dynamic_type_cache_miss'

BUG=450555, 371125
TBR=inferno@chromium.org

Committed: https://crrev.com/24fd209fd5257d3e3f0a88577dd079b19dcb620b
Cr-Commit-Position: refs/heads/master@{#312481}

[Nico, 2015-01-21 21:27:55]

thakis@chromium.org changed reviewers:
+ inferno@chromium.org

[Nico, 2015-01-21 21:27:59]

The CQ bit was checked by thakis@chromium.org

[commit-bot: I haz the power, 2015-01-21 21:29:11]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/856423003/1

[inferno, 2015-01-21 21:32:22]

lgtm. thanks!

[commit-bot: I haz the power, 2015-01-21 22:29:41]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-01-21 22:31:47]

Patchset 1 (id:??) landed as
https://crrev.com/24fd209fd5257d3e3f0a88577dd079b19dcb620b
Cr-Commit-Position: refs/heads/master@{#312481}