Subzero: Use C++11 member initializers where practical.

Subzero: Use C++11 member initializers where practical.

Also change the pattern "foo() {}" into "foo() = default;" for ctors and dtors.

Generally avoids initializing unique_ptr<> members to nullptr in a .h file, because that requires knowing the definition of the underlying class which may not be available to all includers.

BUG= none
R=jpp@chromium.org

Committed: https://gerrit.chromium.org/gerrit/gitweb?p=native_client/pnacl-subzero.git;a=commit;h=eafb56cbab02dbf11071efbc56b4a7098bd40dc7

[Jim Stichnoth, 2015-06-22 17:21:30]

stichnot@chromium.org changed reviewers:
+ jpp@chromium.org, jvoung@chromium.org, kschimpf@google.com

[Jim Stichnoth, 2015-06-22 17:21:46]

Sorry for the mind-numbing refactoring CL...

[John, 2015-06-22 17:30:15]

lgtm

[Jim Stichnoth, 2015-06-22 17:35:17]

Rebase

[Jim Stichnoth, 2015-06-22 17:35:27]

Committed patchset #2 (id:20001) manually as
eafb56cbab02dbf11071efbc56b4a7098bd40dc7 (presubmit successful).