Fixes for a couple of ChromeFrame crashes seen in the latest dev channel buil...

Fixes for a couple of ChromeFrame crashes seen in the latest dev channel build. These
crashes occur in the Chrome HTTP stack which is used for uploading UMA data. I could not
repro these crashes though and they seem to occur while posting tasks to a deleted message
loop. Currently we create an io thread on the fly for uploading the uma data and destroy
it when we are done. To workaround this issue we are attempting to create one IO thread
and leave it running. At this point this thread object is leaked as we don't have a good
way of stopping this from the IO thread. Added a TODO in the code to this effect.

I also added a check for whether the ChromeFrameMetricsDataUploader::Initialize function
succeeds as it appears that there are failures on the field due to failure in creating
the unnamed window.

The ChromeFrame metrics service object is no longer a ThreadLocal object.


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=59594

[amit, 2010-09-15 21:12:04]

lgtm