Reset browser.check_default_browser to true when Chrome is the user's default browser

chrome/browser/ui/startup/default_browser_prompt.cc

Index: chrome/browser/ui/startup/default_browser_prompt.cc
diff --git a/chrome/browser/ui/startup/default_browser_prompt.cc b/chrome/browser/ui/startup/default_browser_prompt.cc
index 86a592ba84e1473536ef1258ccad48df782d2f89..84e559a5e4a3776697e5fbb5ea4eba14da61c708 100644
--- a/chrome/browser/ui/startup/default_browser_prompt.cc
+++ b/chrome/browser/ui/startup/default_browser_prompt.cc
@@ -14,6 +14,7 @@
 #include "chrome/browser/first_run/first_run.h"
 #include "chrome/browser/infobars/infobar_service.h"
 #include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/shell_integration.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_finder.h"
@@ -194,8 +195,16 @@ void NotifyNotDefaultBrowserCallback(chrome::HostDesktopType desktop_type) {
           ShellIntegration::SET_DEFAULT_INTERACTIVE));
 }
 
-void CheckDefaultBrowserCallback(chrome::HostDesktopType desktop_type) {
-  if (ShellIntegration::GetDefaultBrowser() == ShellIntegration::NOT_DEFAULT) {
+void CheckDefaultBrowserCallback(bool show_prompt,
+                                 chrome::HostDesktopType desktop_type) {
+  ShellIntegration::DefaultWebClientState state =
+      ShellIntegration::GetDefaultBrowser();
+  if (state == ShellIntegration::IS_DEFAULT) {
+    // Notify the user in the future if Chrome ceases to be the user's chosen
+    // default browser.
+    PrefService* prefs = ProfileManager::GetLastUsedProfile()->GetPrefs();

[msw, 2015/06/16 19:23:01]

It seems odd to change the last used profile, maybe use |profile| from
ShowDefaultBrowserPrompt? (and avoid the profile_manager.h include)

[grt (UTC plus 2), 2015/06/16 19:31:53]

Ah, what I've done here may be unsafe for several reasons since this function is
run on the FILE thread, so it probably shouldn't touch the Profile* or its
prefs. Is it safe for CheckDefaultBrowserCallback to take the Profile* from
ShowDefaultBrowserPrompt and bounce it back to the UI thread to update the pref?
Could the Profile* have gone away during the bounce to/from the FILE thread?
This is why I involved the ProfileManager: in the normal case it will be the
same Profile*. If not, it will at least be some sensible Profile*.

[msw, 2015/06/16 20:29:49]

Maybe use profile->GetPath(), like ProfileSizeTask and NukeProfileFromDisk?

[grt (UTC plus 2), 2015/06/16 21:04:09]

Done.

+    prefs->SetBoolean(prefs::kCheckDefaultBrowser, true);
+  } else if (show_prompt && state == ShellIntegration::NOT_DEFAULT) {
     ShellIntegration::DefaultWebClientSetPermission default_change_mode =
         ShellIntegration::CanSetAsDefaultBrowser();
 
@@ -218,12 +227,13 @@ void RegisterDefaultBrowserPromptPrefs(PrefRegistrySimple* registry) {
 
 void ShowDefaultBrowserPrompt(Profile* profile, HostDesktopType desktop_type) {
   // We do not check if we are the default browser if:
-  // - The user said "don't ask me again" on the infobar earlier.
   // - There is a policy in control of this setting.
+  // We check if we are the default browser but do not prompt if:
+  // - The user said "don't ask me again" on the infobar earlier.
   // - The "suppress_default_browser_prompt_for_version" master preference is
   //     set to the current version.
-  if (!profile->GetPrefs()->GetBoolean(prefs::kCheckDefaultBrowser))
-    return;
+  bool show_prompt =
+      profile->GetPrefs()->GetBoolean(prefs::kCheckDefaultBrowser);
 
   if (g_browser_process->local_state()->IsManagedPreference(
       prefs::kDefaultBrowserSettingEnabled)) {
@@ -248,12 +258,12 @@ void ShowDefaultBrowserPrompt(Profile* profile, HostDesktopType desktop_type) {
   if (disable_version.IsValid()) {
     const chrome::VersionInfo version_info;
     if (disable_version.Equals(Version(version_info.Version())))
-      return;
+      show_prompt = false;

[msw, 2015/06/16 19:23:01]

nit: show_prompt &= disable_version.Equals(Version(version_info.Version()));

[grt (UTC plus 2), 2015/06/16 19:31:53]

I don't like that pattern since it's using a bitwise-AND on bools. It's a bit
subtle (it works because of bool->int->bool conversions).

   }
 
   content::BrowserThread::PostTask(
       content::BrowserThread::FILE, FROM_HERE,
-      base::Bind(&CheckDefaultBrowserCallback, desktop_type));
+      base::Bind(&CheckDefaultBrowserCallback, show_prompt, desktop_type));
 }
 
 #if !defined(OS_WIN)