Handle upgrade case from previous MSI install.

chrome/installer/setup/setup_main.cc

 // 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.
 
 #include "chrome/installer/setup/setup_main.h"
 
 #include <windows.h>
 #include <msi.h>
 #include <shellapi.h>
 #include <shlobj.h>
@@ skipping 73 matching lines @@
     MiniDumpWithProcessThreadData |  // Get PEB and TEB.
     MiniDumpWithUnloadedModules |  // Get unloaded modules when available.
     MiniDumpWithIndirectlyReferencedMemory);  // Get memory referenced by stack.
 
 namespace {
 
 const wchar_t kGoogleUpdatePipeName[] = L"\\\\.\\pipe\\GoogleCrashServices\\";
 const wchar_t kSystemPrincipalSid[] = L"S-1-5-18";
 const wchar_t kDisplayVersion[] = L"DisplayVersion";
 const wchar_t kMsiDisplayVersionOverwriteDelay[] = L"10";  // seconds as string
+const wchar_t kMsiProductIdPrefix[] = L"EnterpriseProduct";
 
 // Overwrite an existing DisplayVersion as written by the MSI installer
 // with the real version number of Chrome.
 LONG OverwriteDisplayVersion(const base::string16& path,
                              const base::string16& value,
                              REGSAM wowkey) {
   base::win::RegKey key;
   LONG result = 0;
   base::string16 existing;
   if ((result = key.Open(HKEY_LOCAL_MACHINE, path.c_str(),
@@ skipping 98 matching lines @@
   // Specify an empty path for the patch source since it isn't yet known that
   // one is needed. It will be supplied in UncompressAndPatchChromeArchive if it
   // is.
   return scoped_ptr<installer::ArchivePatchHelper>(
       new installer::ArchivePatchHelper(working_directory,
                                         compressed_archive,
                                         base::FilePath(),
                                         target));
 }
 
+base::string16 FindMsiProductId(const InstallerState& installer_state,

[grt (UTC plus 2), 2015/10/09 13:16:39]

please include robert's excellent doc comment for this function:

// Returns the MSI product ID from the ClientState key that is populated for MSI
// installs. This property is encoded in a value name whose format is
// "EnterpriseId<GUID>" where <GUID> is the MSI product id. <GUID> is in the
// format XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX. The id will be returned if found
// otherwise this method will return an empty string.
//
// This format is strange and its provenance is shrouded in mystery but it has
// the data we need, so use it.

[bcwhite, 2015/10/09 19:16:51]

Done.

+                                const Product* product) {
+  HKEY reg_root = installer_state.root_key();
+  BrowserDistribution* dist = product->distribution();
+  DCHECK(dist);
+
+  base::win::RegistryValueIterator value_iter(reg_root,
+                                              dist->GetStateKey().c_str());
+  for (; value_iter.Valid(); ++value_iter) {
+    base::string16 value_name(value_iter.Name());
+    if (base::StartsWith(
+         value_name, kMsiProductIdPrefix, base::CompareCase::INSENSITIVE_ASCII))
+      return value_name.substr(arraysize(kMsiProductIdPrefix) - 1);

[grt (UTC plus 2), 2015/10/09 13:16:39]

nit: braces around this

[bcwhite, 2015/10/09 19:16:51]

Done.

+  }
+  return base::string16();
+}
+
 // Workhorse for producing an uncompressed archive (chrome.7z) given a
 // chrome.packed.7z containing either a patch file based on the version of
 // chrome being updated or the full uncompressed archive. Returns true on
 // success, in which case |archive_type| is populated based on what was found.
 // Returns false on failure, in which case |install_status| contains the error
 // code and the result is written to the registry (via WriteInstallerResult).
 bool UncompressAndPatchChromeArchive(
     const installer::InstallationState& original_state,
     const installer::InstallerState& installer_state,
     installer::ArchivePatchHelper* archive_helper,
@@ skipping 1425 matching lines @@
     for (Products::const_iterator it = products.begin(); it < products.end();
          ++it) {
       const Product& product = **it;
       product.LaunchUserExperiment(setup_path, install_status, system_install);
     }
   }
 
   // If the installation completed successfully...
   if (InstallUtil::GetInstallReturnCode(install_status) == 0) {
     // Update the DisplayVersion created by an MSI-based install.
+    base::FilePath master_preferences_file(
+      installer_state.target_path().AppendASCII(
+          installer::kDefaultMasterPrefs));
     std::string install_id;
     if (prefs.GetString(installer::master_preferences::kMsiProductId,
                         &install_id)) {
+      // A currently active MSI install will have specified the master-
+      // preferences file on the command-line that includes the product-id.
+      // We must delay the setting of the DisplayVersion until after the
+      // grandparent "msiexec" process has exited.
       base::FilePath new_setup =
           installer_state.GetInstallerDirectory(*installer_version)
           .Append(kSetupExe);
       DelayedOverwriteDisplayVersions(
           new_setup, install_id, *installer_version);
+    } else {
+      // Only when called by the MSI installer do we need to delay setting
+      // the DisplayVersion.  In other runs, such as those done by the auto-
+      // update action, we set the value immediately.
+      const Product* chrome = installer_state.FindProduct(
+          BrowserDistribution::CHROME_BROWSER);
+      if (chrome != NULL) {
+        // Get the app's GUID from an entry in ClientState

[grt (UTC plus 2), 2015/10/09 13:16:39]

nit:
        // Get the app's MSI product ID from EnterpriseProduct in ClientState.

[bcwhite, 2015/10/09 19:16:51]

Done.

+        base::string16 app_guid = FindMsiProductId(installer_state, chrome);
+        if (!app_guid.empty()) {
+          OverwriteDisplayVersions(app_guid,
+                                   base::UTF8ToUTF16(
+                                       installer_version->GetString()));
+        }
+      }
     }
     // Return the path to the directory containing the newly installed
     // setup.exe and uncompressed archive if the caller requested it.
     if (installer_directory) {
       *installer_directory =
           installer_state.GetInstallerDirectory(*installer_version);
     }
   }
 
   // temp_path's dtor will take care of deleting or scheduling itself for
@@ skipping 151 matching lines @@
     // Note that we allow the status installer::UNINSTALL_REQUIRES_REBOOT
     // to pass through, since this is only returned on uninstall which is
     // never invoked directly by Google Update.
     return_code = InstallUtil::GetInstallReturnCode(install_status);
   }
 
   VLOG(1) << "Installation complete, returning: " << return_code;
 
   return return_code;
 }