Fix error from syntax checking

This fixes the confict of decalaration and definition between class
and struct. It also fixes the virtual function overloading.

BUG=chromium:218316
TEST=USE="chrome_internal" CFLAGS="-clang -print-cmdline"
     CXXFLAGS="-clang -print-cmdline" emerge-x86-alex
     gobi-cromo-plugin
     passes.

Change-Id: I5109af3aff4052477b2e255b45ab06537e306527
Reviewed-on: https://gerrit.chromium.org/gerrit/47482
Reviewed-by: Thieu Le <thieule@chromium.org>
Tested-by: Yunlian Jiang <yunlian@chromium.org>
Commit-Queue: Yunlian Jiang <yunlian@chromium.org>
5 files changed