Support dropping of files onto chrome://tracing.
Support dropping of files onto chrome://tracing.

Add a drop handler to the profile_view. When you drop a file it will
be parsed and the UI updated to reflect the new data.

BUG=112
R=nduca@chromium.org

Review URL: https://codereview.appspot.com/7299068

git-svn-id: 3a56fcae908c7e16d23cb53443ea4795ac387cf2@385 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