browser: Fix occasional NPE

view.getUrl() may sometimes return null.  syncCurrentState() checks for
null when setting mCurrentState.mUrl so use that instead.

Change-Id: I487249c6665d192b3c95e09a0b64ee840202f127
Merge remote-tracking branch 'cm/cm-11.0' into cm-11.0
Merge pull request #5 from androidarmv6/cm-11.0

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