Add a callback to report whether ExceptionHandler initialization passed or failed

[GoogleCodeExporter]

We are seeing data where breakpad is not able to handle the crashes. This 
defect can be device specific. We want to capture the different scenarios where 
breakpad could have failed. One of them is the initialization of 
ExceptionHandler. There should be a callback or a return value stating whether 
the initialization succeeded or failed.

Original issue reported on code.google.com by [email protected] on 31 Mar 2015 at 8:01