New experiment without registry deletion

chrome/browser/shell_integration_win.cc

Index: chrome/browser/shell_integration_win.cc
diff --git a/chrome/browser/shell_integration_win.cc b/chrome/browser/shell_integration_win.cc
index 04bc80c220d314d2a3c7074f0c420cbde1eb233b..85b692e95463838ce125b33db12074cdc3c8c8cc 100644
--- a/chrome/browser/shell_integration_win.cc
+++ b/chrome/browser/shell_integration_win.cc
@@ -253,25 +253,6 @@ ShellIntegration::DefaultWebClientState
   }
 }
 
-// Resets the default browser choice for the current user.
-void ResetDefaultBrowser() {
-  static const wchar_t* const kUrlAssociationKeyFormats[] = {
-      L"SOFTWARE\\Microsoft\\Windows\\Shell\\Associations\\UrlAssociations\\"
-      L"%ls\\UserChoice",
-      L"SOFTWARE\\Microsoft\\Windows\\Roaming\\OpenWith\\UrlAssociations\\"
-      L"%ls\\UserChoice"};
-  static const wchar_t* const kProtocols[] = {L"http", L"https"};
-
-  for (const wchar_t* format : kUrlAssociationKeyFormats) {
-    for (const wchar_t* protocol : kProtocols) {
-      base::win::RegKey registry_key(
-          HKEY_CURRENT_USER, base::StringPrintf(format, protocol).c_str(),
-          KEY_SET_VALUE);
-      registry_key.DeleteValue(L"Hash");
-    }
-  }
-}
-
 // Returns true if the AsyncSetAsDefault field trial is activated.
 bool IsAsyncSetAsDefaultEnabled() {
   using base::CommandLine;
@@ -279,7 +260,7 @@ bool IsAsyncSetAsDefaultEnabled() {
   // Note: It's important to query the field trial state first, to ensure that
   // UMA reports the correct group.
   const std::string group_name =
-      base::FieldTrialList::FindFullName("AsyncSetAsDefault");
+      base::FieldTrialList::FindFullName(kAsyncSetAsDefaultExperimentName);
   if (CommandLine::ForCurrentProcess()->HasSwitch(kDisableAsyncSetAsDefault))
     return false;
   if (CommandLine::ForCurrentProcess()->HasSwitch(kEnableAsyncSetAsDefault))
@@ -300,6 +281,32 @@ bool RegisterBrowser() {
                                           true);
 }
 
+// Returns true if the default browser choice should be reset for the current
+// user.
+bool ShouldResetDefaultBrowser() {
+  return base::FieldTrialList::FindFullName(kAsyncSetAsDefaultExperimentName) !=
+         "EnabledNoRegistry";

[gab, 2016/01/11 23:41:00]

Use StartsWith() instead of == for comparing group names (more flexible server
side after)

[Patrick Monette, 2016/01/12 00:07:27]

Done.

+}
+
+// Resets the default browser choice for the current user.
+void ResetDefaultBrowser() {

[gab, 2016/01/11 23:41:00]

What's the reason to move the method? It appears unchanged but makes this diff
bigger..?

[Patrick Monette, 2016/01/12 00:07:27]

Just to make order of definition = order of use.

+  static const wchar_t* const kUrlAssociationKeyFormats[] = {
+      L"SOFTWARE\\Microsoft\\Windows\\Shell\\Associations\\UrlAssociations\\"
+      L"%ls\\UserChoice",
+      L"SOFTWARE\\Microsoft\\Windows\\Roaming\\OpenWith\\UrlAssociations\\"
+      L"%ls\\UserChoice"};
+  static const wchar_t* const kProtocols[] = {L"http", L"https"};
+
+  for (const wchar_t* format : kUrlAssociationKeyFormats) {
+    for (const wchar_t* protocol : kProtocols) {
+      base::win::RegKey registry_key(
+          HKEY_CURRENT_USER, base::StringPrintf(format, protocol).c_str(),
+          KEY_SET_VALUE);
+      registry_key.DeleteValue(L"Hash");
+    }
+  }
+}
+
 }  // namespace
 
 // static
@@ -720,7 +727,8 @@ bool ShellIntegration::DefaultBrowserWorker::SetAsDefaultBrowserAsynchronous() {
   if (!RegisterBrowser())
     return false;
 
-  ResetDefaultBrowser();
+  if (ShouldResetDefaultBrowser())
+    ResetDefaultBrowser();
 
   base::CommandLine cmdline(base::FilePath(L"openwith.exe"));
   cmdline.AppendArgNative(StartupBrowserCreator::GetDefaultBrowserUrl());