Add an experiment for the default browser infobar on Windows 10

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 8765d386d80a1a3dbbaa14a796fac3be68b70d32..b6dd2b002ca7c4092c5455159e8fb0490776490a 100644
--- a/chrome/browser/ui/startup/default_browser_prompt.cc
+++ b/chrome/browser/ui/startup/default_browser_prompt.cc
@@ -4,6 +4,7 @@
 
 #include "chrome/browser/ui/startup/default_browser_prompt.h"
 
+#include <limits>

[Patrick Monette, 2016/05/12 23:43:25]

This fixes a lint error.

 #include <string>
 
 #include "base/location.h"
@@ -39,11 +40,25 @@
 #include "ui/gfx/vector_icons_public.h"
 
 #if defined(OS_WIN)
+#include "base/feature_list.h"
 #include "base/win/windows_version.h"
 #endif
 
 namespace {
 
+bool IsStickyDefaultBrowserInfobarEnabled() {
+#if defined(OS_WIN)
+  static const base::Feature kStickyDefaultBrowserInfobar{

[Peter Kasting, 2016/05/17 03:07:37]

Nit: Can be constexpr

[Patrick Monette, 2016/05/31 15:19:41]

I can't manage to make it constexpr now that I'm declaring it in the header
file.

+      "StickyDefaultBrowserInfobar", base::FEATURE_DISABLED_BY_DEFAULT};
+
+  // The flow to set the default browser is only asynchronous on Windows 10+.
+  return base::win::GetVersion() >= base::win::VERSION_WIN10 &&
+         base::FeatureList::IsEnabled(kStickyDefaultBrowserInfobar);
+#else
+  return false;
+#endif
+}
+
 // The delegate for the infobar shown when Chrome is not the default browser.
 // Ownership of the delegate is given to the infobar itself, the lifetime of
 // which is bound to the containing WebContents.
@@ -86,6 +101,12 @@ class DefaultBrowserInfoBarDelegate : public ConfirmInfoBarDelegate {
   bool Accept() override;
   bool Cancel() override;
 
+  // Removes the infobar when the worker is finished setting the default
+  // browser. Only used if the StickyDefaultBrowserInfobar experiment is
+  // enabled.
+  void OnSetAsDefaultFinished(
+      shell_integration::DefaultWebClientState /* state */);

[Peter Kasting, 2016/05/17 03:07:37]

Nit: No /* */; put the name uncommented here and below.  (Chromium does not warn
on unused named params.)

[Patrick Monette, 2016/05/31 15:19:41]

Done.

+
   // The WebContents's corresponding profile.
   Profile* profile_;
 
@@ -192,14 +213,26 @@ bool DefaultBrowserInfoBarDelegate::Accept() {
   UMA_HISTOGRAM_ENUMERATION("DefaultBrowser.InfoBar.UserInteraction",
                             ACCEPT_INFO_BAR,
                             NUM_INFO_BAR_USER_INTERACTION_TYPES);
+
+  bool close_infobar = true;
+  shell_integration::DefaultWebClientWorkerCallback set_as_default_callback;
+
+  if (IsStickyDefaultBrowserInfobarEnabled()) {
+    // When the experiment is enabled, the infobar is only closed when the
+    // DefaultBrowserWorker is finished.
+    set_as_default_callback =
+        base::Bind(&DefaultBrowserInfoBarDelegate::OnSetAsDefaultFinished,
+                   weak_factory_.GetWeakPtr());
+    close_infobar = false;
+  }
+
   // The worker pointer is reference counted. While it is running, the
   // message loops of the FILE and UI thread will hold references to it
   // and it will be automatically freed once all its tasks have finished.
   scoped_refptr<shell_integration::DefaultBrowserWorker>(
-      new shell_integration::DefaultBrowserWorker(
-          shell_integration::DefaultWebClientWorkerCallback()))
+      new shell_integration::DefaultBrowserWorker(set_as_default_callback))
       ->StartSetAsDefault();
-  return true;
+  return close_infobar;
 }
 
 bool DefaultBrowserInfoBarDelegate::Cancel() {
@@ -212,6 +245,11 @@ bool DefaultBrowserInfoBarDelegate::Cancel() {
   return true;
 }
 
+void DefaultBrowserInfoBarDelegate::OnSetAsDefaultFinished(
+    shell_integration::DefaultWebClientState /* state */) {
+  infobar()->owner()->RemoveInfoBar(infobar());
+}
+
 void ResetCheckDefaultBrowserPref(const base::FilePath& profile_path) {
   Profile* profile =
       g_browser_process->profile_manager()->GetProfileByPath(profile_path);