Add -[BreakpadController setParametersToAddAtUploadTime:] for iOS.

This provides the ability to add server parameters to a crash report when the
report is uploaded.

Patch by KiYun Roe <kiyun@chromium.org>

BUG=558
R=blundell@chromium.org

Review URL: https://breakpad.appspot.com/974002/

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1271 4c0a9323-5329-0410-9bdc-e9ce6186880e