[Courgette] Refactor BSDiff namespaces and bsdiff::search() interface.

chrome/installer/setup/setup_util.cc

Index: chrome/installer/setup/setup_util.cc
diff --git a/chrome/installer/setup/setup_util.cc b/chrome/installer/setup/setup_util.cc
index 75cc8a61e01e8a33c2e164aeb3b3aec81f3a3b1d..f55c8629afd660a1ef5e0172d5fe5a880c1595b6 100644
--- a/chrome/installer/setup/setup_util.cc
+++ b/chrome/installer/setup/setup_util.cc
@@ -37,7 +37,6 @@
 #include "chrome/installer/util/util_constants.h"
 #include "courgette/courgette.h"
 #include "courgette/third_party/bsdiff/bsdiff.h"
-#include "third_party/bspatch/mbspatch.h"
 
 namespace installer {
 
@@ -87,8 +86,8 @@ int BsdiffPatchFiles(const base::FilePath& src,
   if (src.empty() || patch.empty() || dest.empty())
     return installer::PATCH_INVALID_ARGUMENTS;
 
-  const int patch_status = courgette::ApplyBinaryPatch(src, patch, dest);
-  const int exit_code = patch_status != OK ?
+  const int patch_status = bsdiff::ApplyBinaryPatch(src, patch, dest);
+  const int exit_code = patch_status != bsdiff::OK ?

[huangs, 2016/06/03 05:12:05]

This was Frankenstein before: Using BSDiff from Courgette, but OK from BSPatch.
Having the bsdiff namespace is nice.

However, chrome/installer/setup/archive_patch_helper.cc still uses MBSPatch.  I
left it alone, but it's odd that Installer is using both Courgette and BSPatch
versions?

[grt (UTC plus 2), 2016/06/03 15:58:36]

Maybe we can get rid of the use of mbspatch in archive_patch_helper now. mmoss:
is my understanding correct that we now only build what was once called the
"3-stage" diff updater? Is there any reason not to ditch the code in Chrome that
handles the non-3-stage variant?

[Michael Moss, 2016/06/03 16:40:20]

Correct, we've only had 3-stage for many months now. There is still code to
generate the others, but it's disabled by default, and I'd be more than happy to
remove it entirely.

                         patch_status + kBsdiffErrorOffset : 0;
 
   LOG_IF(ERROR, exit_code)