Always suffix ChromeHTML entries on Windows for user-level installs.

chrome/installer/util/shell_util.h

Index: chrome/installer/util/shell_util.h
diff --git a/chrome/installer/util/shell_util.h b/chrome/installer/util/shell_util.h
index 85e5fbd7d0f9e8123a5e2b2157810f3ad4ede95f..c4b71b3aef96a63d1f39a0859d8bfb42f54c3406 100644
--- a/chrome/installer/util/shell_util.h
+++ b/chrome/installer/util/shell_util.h
@@ -204,15 +204,42 @@ class ShellUtil {
   static void GetRegisteredBrowsers(BrowserDistribution* dist,
                                     std::map<string16, string16>* browsers);
 
-  // This function gets a suffix (user's login name) that can be added
-  // to Chromium default browser entry in the registry to create a unique name
-  // if there are multiple users on the machine, each with their own copy of
-  // Chromium that they want to set as default browser.
-  // This suffix value is assigned to |entry|. The function also checks for
-  // existence of Default Browser registry key with this suffix and
-  // returns true if it exists. In all other cases it returns false.
-  static bool GetUserSpecificDefaultBrowserSuffix(BrowserDistribution* dist,
-                                                  string16* entry);
+  // Returns the suffix this user's Chrome install is registered with.
+  // Note: this method returns the empty string on system-level installs by
+  // design as no system-level installs is ever suffixed.
+  //
+  // This method is meant for external methods which need to know the suffix of
+  // the current install at run-time, not for install-time decisions.
+  // There are no guarantees that this suffix will not change later:
+  // (e.g. if two user-level installs were previously installed in parallel on
+  // the same machine, both without admin rights and with no user-level install
+  // having claimed the non-suffixed HKLM registrations, they both have no
+  // suffix in their progId entries (as per the old suffix rules). If they were
+  // to both fully register (i.e. click "Make Chrome Default" and go through
+  // UAC; or upgrade to Win8 and get the automatic no UAC full registration)
+  // they would then both get a suffixed registration as per the new suffix
+  // rules).
+  static string16 GetCurrentInstallationSuffix();
+
+  // Returns true if the current user-level install has been fully registered
+  // without a suffix. This is used to support old installs where we used to
+  // not suffix user-level installs if they were the first to request the
+  // non-suffixed registry entries on the machine. This however created clashes
+  // with system-level installs when updating user-level installs to
+  // system-level installs. There is no downside to suffixing anyways (the name
+  // registered is not user visible).
+  // All the conditions below have to be true for it to return true:
+  // - Software\Clients\StartMenuInternet\Chromium\"" key should have a valid
+  //   value.
+  // - The value should be same as given value in |chrome_exe|.
+  static bool CurrentUserIsRegisteredWithNoSuffix(BrowserDistribution* dist,
+                                                  const string16& chrome_exe);
+
+  // Returns true if any of the possible Chrome registry keys are present in
+  // HKLM with |suffix|.
+  static bool IsInstallationPresentInHKLM(BrowserDistribution* dist,
+                                          const string16& chrome_exe,
+                                          const string16& suffix);
 
   // Make Chrome the default browser. This function works by going through
   // the url protocols and file associations that are related to general