[Android] Fix the issue about file picker does not work.

This patch is to fix the issue about file picker does not work.
Upstream has added content URI to upload photos taken by camera,
so we follow it.

BUG=XWALK-2631
In ContentUriUtils.java under folder "base/android/java/src/org/chromium/base", it create a new interface named "FileProviderUtil", so we should implement it to supply "getContentUriFromFile()".
For FileProviderHelper.java, I copy it from chrome/android/java/src/org/chromium/chrome/browser/FileProviderHelper.java, or we can add dependency with "chrome.gyp:chrome_java".