use NetAsyncSlice for disabled-by-default-netlog category
Merge pull request #643 from xunjieli/disabled-by-default-netlog

use NetAsyncSlice for disabled-by-default-netlog category
Add WriteHTMLForTraceDataToFile method that allow create trace viewer in html directly from trace data
Expose URL to top level async slices
addressed comments
Merge pull request #642 from xunjieli/exposeURLAsSliceTitle

Expose URL as the title of toplevel async slices
Update trac2html so that WriteHTMLForTracesToFile calls WriteHTMLForTraceDataToFile
Merge pull request #644 from NghiaNguyen/master

Add WriteHTMLForTraceDataToFile method.