unrar: Use CHECK(false) instead of explicitly terminating process.

No change to README.chromium required since it already contains:
- Replace exceptions with terminating the current process. Guarded with the
  macro UNRAR_NO_EXCEPTIONS.

R=wfh

Bug: 750327,847635,767906
Change-Id: Ie5efe8b637f87647ea2972c115a2ac2464ef793d
Reviewed-on: https://chromium-review.googlesource.com/1081434Reviewed-by: Will Harris <wfh@chromium.org>
Commit-Queue: Varun Khaneja <vakh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#565082}

third_party/unrar/src/errhnd.cpp

 // NOTE(vakh): The process.h file needs to be included first because "rar.hpp"
 // defines certain macros that cause symbol redefinition errors
 #if defined(UNRAR_NO_EXCEPTIONS)
+#include "base/logging.h"
 #include "base/process/process.h"
 #endif  // defined(UNRAR_NO_EXCEPTIONS)
 
@@ -321,7 +322,7 @@ void ErrorHandler::Throw(RAR_EXIT Code)
 #endif
   SetErrorCode(Code);
 #if defined(UNRAR_NO_EXCEPTIONS)
-  base::Process::Current().Terminate(Code, false);
+  CHECK(false) << "Failed with RAR_EXIT code: " << Code;
 #else
   throw Code;
 #endif  // defined(UNRAR_NO_EXCEPTIONS)