XmlUtil: Report all parsing errors

Detect all XML parsing errors in XmlUtil and raise exceptions for them.
Changes in the CL:
1. Add new |gotoNextSection|* methods to raise exception when it does
not find a section with the expected tag name.
2. Raise exceptions for all errors in |WifiConfigurationXmlUtil|, etc.
3. |IpConfiguration| can never be null in WifiConfiguratin object, so
remove the conditional check in WifiBackupRestore.

While there,
Shorten the method names in |WifiConfigurationXmlUtil|, etc to
parseFromXml/writeToXml.

BUG: 29312911
Change-Id: I5bb152e9757f039410dd81afebaad009644e1414
TEST: Unit tests
3 files changed
tree: ec86f7786231172add8521652bff65758f16a6f3
  1. service/
  2. tests/