Toss FLOW events until proper support arrives.
Toss FLOW events until proper support arrives.

Explicitly discard 's', 't', and 'f' events so parsing isn't slowed down
generating import errors for the FLOW events.

BUG=none
TEST=load a trace w/ FLOW events and verify import errors are no longer filled with complaints

Change-Id: Ibfcfeea2773e8e4990213d600737bc63f76318e6

Review URL: https://codereview.appspot.com/6592070

git-svn-id: 3a56fcae908c7e16d23cb53443ea4795ac387cf2@174 0e6d7f2b-9903-5b78-7403-59d27f066143

bpsinc-native/src_third_party_trace-viewer,bpsinc-native/src_third_party_trace-viewer,bpsinc-native/src_third_party_trace-viewer,bpsinc-native/src_third_party_trace-viewer