Merge pull request #443 from google/rsturgell

Add data source for chrome dev tools cpu profiles.
Call/memory tracing in the extension.
Buttons right in the WTF popup to instrument calls/memory! Woo! It only
supports synchronous appended script blocks right now, but that's most of
Maps.
This needs some code sharing work with the command line version (that
is still useful for other browsers), and a lot of performance improvements.
It also cannot capture all scripts and apps using it will need some
minor changes in their loaders.
Merge pull request #444 from google/extension_tracing

Call/memory tracing in the extension.
Adding support for async scripts.
It's missing some cases still, but works well enough for maps.
Merge pull request #445 from google/extension_tracing

Adding support for async scripts.
Latest closure tools.
Since it's embedded on the page, no need for the injection style.