Give SxS distribution its own registration GUIDs.

chrome/installer/util/install_util.cc

Index: chrome/installer/util/install_util.cc
diff --git a/chrome/installer/util/install_util.cc b/chrome/installer/util/install_util.cc
index c8c037df823364a081b3ebac240cb974244d3e27..91b2c28c9badec05a0cf34170fcbc40111f9f12e 100644
--- a/chrome/installer/util/install_util.cc
+++ b/chrome/installer/util/install_util.cc
@@ -365,10 +365,23 @@ bool CheckIsChromeSxSProcess() {
   PathService::Get(base::DIR_EXE, &exe_dir);
   string16 chrome_sxs_dir(installer::kGoogleChromeInstallSubDir2);
   chrome_sxs_dir.append(installer::kSxSSuffix);
-  return base::FilePath::CompareEqualIgnoreCase(
-          exe_dir.BaseName().value(), installer::kInstallBinaryDir) &&
-      base::FilePath::CompareEqualIgnoreCase(
-          exe_dir.DirName().BaseName().value(), chrome_sxs_dir);
+
+  // This is SxS if current EXE is in or under (possibly multiple levels under)
+  // |chrome_sxs_dir|\|installer::kInstallBinaryDir|
+  typedef std::vector<base::FilePath::StringType>::const_reverse_iterator

[gab, 2013/09/11 21:26:29]

I would put the typedef right before the for loop since it's only used for it.

+      ComponentsIterator;
+  std::vector<base::FilePath::StringType> components;
+  exe_dir.GetComponents(&components);
+  for (ComponentsIterator current = components.rbegin(), parent = current+1;

[gab, 2013/09/11 21:26:29]

Need to check:

if (components.size() < 2)
  return false;

before doing this or current+1 might not exist if current == rend().

Technically checking !components.empty() is sufficient to ensure that, but if
checking size, might as well check that it's not < 2 in which case we can't
succeed anyways...

[gab, 2013/09/11 21:26:29]

Spaces on each side of '+' sign.

+       parent != components.rend(); current = parent++) {
+    if (base::FilePath::CompareEqualIgnoreCase(*current,

[grt (UTC plus 2), 2013/09/11 21:39:34]

move *current to next line as was done in uninstall.cc (indented four spaces
from the 'b' in "base::FilePath")?

+        installer::kInstallBinaryDir)) {
+      if (base::FilePath::CompareEqualIgnoreCase(*parent, chrome_sxs_dir))

[gab, 2013/09/11 21:26:29]

Use && instead of nesting ifs.

+        return true;
+    }
+  }
+
+  return false;
 }
 
 bool InstallUtil::IsChromeSxSProcess() {