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

chrome/installer/util/shell_util.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // This file declares methods that are useful for integrating Chrome in
 // Windows shell. These methods are all static and currently part of
 // ShellUtil class.
 
 #ifndef CHROME_INSTALLER_UTIL_SHELL_UTIL_H_
 #define CHROME_INSTALLER_UTIL_SHELL_UTIL_H_
@@ skipping 186 matching lines @@
   // returns false. If system_level is true this function returns the path
   // to Default Users Quick Launch shortcuts path. Adding a shortcut to Default
   // User's profile only affects any new user profiles (not existing ones).
   static bool GetQuickLaunchPath(bool system_level, FilePath* path);
 
   // Gets a mapping of all registered browser (on local machine) names and
   // their reinstall command (which usually sets browser as default).
   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.
+  // Always returns the empty string on system-level installs.
+  //
+  // 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).
+  //
+  // |chrome_exe| The path to the currently installed (or running) chrome.exe.
+  static string16 GetCurrentInstallationSuffix(BrowserDistribution* dist,
+                                               const string16& chrome_exe);
+
+  // An enum used to tell CurrentUserIsRegisteredWithSuffix() which level of

[grt (UTC plus 2), 2012/06/08 16:24:13]

CurrentUserIsRegisteredWithSuffix -> QuickIsChromeRegistered

[gab, 2012/06/08 20:15:51]

Done.

+  // registration we want to confirm.
+  enum RegistrationConfirmationLevel {

[grt (UTC plus 2), 2012/06/08 16:24:13]

chromium style: enums come before methods in a class.

[gab, 2012/06/08 20:15:51]

Done.

+    // Only look for Chrome's ProgIds.
+    // This is sufficient when we are trying to determine the suffix of the
+    // currently running Chrome as system registrations might not be present.
+    CONFIRM_PROGID_REGISTRATION = 0,
+    // Confirm that Chrome is registered on the system (i.e. registered with
+    // Defaut Programs).
+    CONFIRM_SYSTEM_REGISTRATION,
+  };
+
+  // Returns true if the current install's |chrome_exe| has been registered with
+  // |suffix|.
+  // |confirmation_level| is the level of verification desired as described in
+  // the RegistrationConfirmationLevel enum above.
+  // |suffix| can be the empty string (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).
+  // NOTE: This a quick check that only validates that a single registry entry
+  // points to |chrome_exe|. This should only be used at run-time to determine
+  // how Chrome is registered, not to know whether the registration is complete
+  // at install-time (IsChromeRegistered() can be used for that).
+  static bool QuickIsChromeRegistered(

[grt (UTC plus 2), 2012/06/08 16:24:13]

Looks like you can simplify things if you remove RegistrationConfirmationLevel
and turn this into two functions that make the different checks. 
IsChromeBrowserRegistered() could be the name of the one declared here that
checks the system registration.  The variation that only checks the ProgID
registration can be a private helper in the unnamed namespace that is used only
by GetCurrentInstallationSuffix.

[gab, 2012/06/08 20:15:51]

Thanks for pointing this out, it turns out that with all the rearrangements I've
done this was now only called by uninstall.cc (apart from shell_util.cc itself),
I made it a local function and made a new public function for the uninstall use
as suggested in your uninstall.cc comments.

The idea of a single function is that the code to ProgramCompare with HKCU
preceding HKLM is common to both, only the path looked up is different; even if
I was to split the function I would create a helper function that both functions
call to make the final check (so that'd be 3 functions (maybe 4 given the
special uninstall case) rather than 1 function + an enum).

Given this is now a local function and the enum doesn't put burden on the public
API anymore, I kept it as a single function for now, let me know if you think
otherwise.

+      BrowserDistribution* dist,
+      const string16& chrome_exe,
+      const string16& suffix,
+      RegistrationConfirmationLevel confirmation_level);
 
   // Make Chrome the default browser. This function works by going through
   // the url protocols and file associations that are related to general
   // browsing, e.g. http, https, .html etc., and requesting to become the
   // default handler for each. If any of these fails the operation will return
   // false to indicate failure, which is consistent with the return value of
   // ShellIntegration::IsDefaultBrowser.
   //
   // In the case of failure any successful changes will be left, however no
   // more changes will be attempted.
@@ skipping 118 matching lines @@
                                    const string16& icon_path,
                                    int icon_index,
                                    uint32 options);
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ShellUtil);
 };
 
 
 #endif  // CHROME_INSTALLER_UTIL_SHELL_UTIL_H_