Force migrate all clients from multi-install back to single-install.

chrome/installer/util/master_preferences.cc

Index: chrome/installer/util/master_preferences.cc
diff --git a/chrome/installer/util/master_preferences.cc b/chrome/installer/util/master_preferences.cc
index 8ec3e04ece6f82072f1e24ce04a682f5d69b0a7b..f71c3000a012994aebbcbc4c915d346ff131193f 100644
--- a/chrome/installer/util/master_preferences.cc
+++ b/chrome/installer/util/master_preferences.cc
@@ -75,34 +75,19 @@ base::DictionaryValue* ParseDistributionPreferences(
 
 namespace installer {
 
-MasterPreferences::MasterPreferences() : distribution_(NULL),
-                                         preferences_read_from_file_(false),
-                                         chrome_(true),
-                                         multi_install_(false) {
+MasterPreferences::MasterPreferences() {
   InitializeFromCommandLine(*base::CommandLine::ForCurrentProcess());
 }
 
-MasterPreferences::MasterPreferences(const base::CommandLine& cmd_line)
-    : distribution_(NULL),
-      preferences_read_from_file_(false),
-      chrome_(true),
-      multi_install_(false) {
+MasterPreferences::MasterPreferences(const base::CommandLine& cmd_line) {
   InitializeFromCommandLine(cmd_line);
 }
 
-MasterPreferences::MasterPreferences(const base::FilePath& prefs_path)
-    : distribution_(NULL),
-      preferences_read_from_file_(false),
-      chrome_(true),
-      multi_install_(false) {
+MasterPreferences::MasterPreferences(const base::FilePath& prefs_path) {
   InitializeFromFilePath(prefs_path);
 }
 
-MasterPreferences::MasterPreferences(const std::string& prefs)
-    : distribution_(NULL),
-      preferences_read_from_file_(false),
-      chrome_(true),
-      multi_install_(false) {
+MasterPreferences::MasterPreferences(const std::string& prefs) {
   InitializeFromString(prefs);
 }
 
@@ -129,14 +114,10 @@ void MasterPreferences::InitializeFromCommandLine(
     const char* cmd_line_switch;
     const char* distribution_switch;
   } translate_switches[] = {
-    { installer::switches::kChrome,
-      installer::master_preferences::kChrome },
     { installer::switches::kDisableLogging,
       installer::master_preferences::kDisableLogging },
     { installer::switches::kMsi,
       installer::master_preferences::kMsi },
-    { installer::switches::kMultiInstall,
-      installer::master_preferences::kMultiInstall },
     { installer::switches::kDoNotRegisterForUpdateLaunch,
       installer::master_preferences::kDoNotRegisterForUpdateLaunch },
     { installer::switches::kDoNotLaunchChrome,
@@ -181,11 +162,14 @@ void MasterPreferences::InitializeFromCommandLine(
     }
   }
 
+  // Strip multi-install from the dictionary, if present.
+  master_dictionary_->Remove(std::string(master_preferences::kDistroDict) +
+                                 '.' + master_preferences::kMultiInstall,

[gab, 2016/12/12 21:38:16]

Why bother stripping it? We're not stripping kChrome nor any other garbage. What
I'd like one day is to only copy a select set to Preferences instead of stomping
it all out there but that's another story.

Also, have we updated online documentation already?

[grt (UTC plus 2), 2016/12/13 09:20:37]

This is an insurance policy against code that looks directly into the
process-wide MasterPreferences dict to check for multi-ness rather than querying
the InstallerState instance. I haven't found any in my various searches, but
that doesn't mean it's not there. :-)

Note that this does not edit the file on disk -- it just serves to keep the
state in-process consistent.
I plan to make a pass on chromium.org sometime after this lands.

[gab, 2016/12/14 16:33:38]

Got it, can you clarify the comment to that effect (i.e. to avoid this turning
into a justification to add stripping code for all-the-things).

+                             nullptr);
+
   // Cache a pointer to the distribution dictionary. Ignore errors if any.
   master_dictionary_->GetDictionary(installer::master_preferences::kDistroDict,
                                     &distribution_);
-
-  InitializeProductFlags();
 #endif
 }
 
@@ -217,30 +201,10 @@ bool MasterPreferences::InitializeFromString(const std::string& json_data) {
         installer::master_preferences::kDistroDict, &distribution_);
   }
 
-  InitializeProductFlags();
   EnforceLegacyPreferences();
   return data_is_valid;
 }
 
-void MasterPreferences::InitializeProductFlags() {
-  // Make sure we start out with the correct defaults.
-  multi_install_ = false;
-  chrome_ = true;
-
-  GetBool(installer::master_preferences::kMultiInstall, &multi_install_);
-
-  // When multi-install is specified, the checks are pretty simple (in theory):
-  // In order to be installed/uninstalled, each product must have its switch
-  // present on the command line.
-  // When multi-install is not set, operate on Chrome.
-  if (multi_install_) {
-    if (!GetBool(installer::master_preferences::kChrome, &chrome_))
-      chrome_ = false;
-  } else {
-    chrome_ = true;
-  }
-}
-
 void MasterPreferences::EnforceLegacyPreferences() {
   // If create_all_shortcuts was explicitly set to false, set
   // do_not_create_(desktop|quick_launch)_shortcut to true.