Use TargetLanguage of the Parser in ImageGallery

If there is a parser set on ImageGallery, the target language of the
parser should be used, because this parsed piece of html can get into
the parser cache.

Change-Id: I2e47b316e3dcc6a3db4fb5d13f5065e35fc369dd
Merge "Use TargetLanguage of the Parser in ImageGallery"