[Android] Move the java content/ package to content_public/ to start the split.

[Android] Move the java content/ package to content_public/ to start the split.

This is one of many steps to try and make the java content package look
more like the c++ counterpart.

The choice of content_public is because public is a reserved keyboard in
java and can not be used in package names (i.e. content.public. is invalid).

BUG=335690

[Ted C, 2014-01-17 22:53:22]

PTAL (be wary that this change contains a TON of files, so it is very slow to
load).

yfriedman|bulach - Overall java direction
benm|boliu - WebView-ness
jam - Sign-off for general consistency with c++ content/public

[Ted C, 2014-01-18 00:59:31]

On 2014/01/17 22:53:22, Ted C wrote:
> PTAL (be wary that this change contains a TON of files, so it is very slow to
> load).
> 
> yfriedman|bulach - Overall java direction
> benm|boliu - WebView-ness
> jam - Sign-off for general consistency with c++ content/public

Scratch that.  After talking more about this, I think this approach isn't what
we should be doing right now.  I think we'll go with a smaller more calculated
move that will allow us to clean up our shame along the way.

I'll outline it in the bug.