Revert 214755 "Clean up PnaclTranslationCache interface"

Revert 214755 "Clean up PnaclTranslationCache interface"

> Clean up PnaclTranslationCache interface
> 
> This CL augments PnaclTranslationCache's public interface into a state
> where it can be used by the PnaclHost. In particular, it adds GetKey
> which generates a cache key from a cache_info object, and it switches
> to using net::DrainableIOBuffer to transfer nexe data, which both
> simplifies the implementation and reduces the number of times the data
> needs to be copied.
> 
> R=jvoung@chromium.org
> BUG= https://code.google.com/p/nativeclient/issues/detail?id=3372
> TEST= unit_tests --gtest_filter=PnaclTranslationCache*
> 
> Review URL: https://chromiumcodereview.appspot.com/21075004

TBR=tbreisacher@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=214762

[Derek Schuff, 2013-07-31 17:21:25]

Committed patchset #1 manually as r214762.

[Mark Seaborn, 2013-07-31 17:50:06]

Why was the change reverted?  Please put an explanation in the commit message or
in the review, otherwise no-one can tell from the change history why a change
was reverted.