Add an experiment for the default browser infobar on Windows 10

chrome/browser/ui/startup/default_browser_infobar_delegate.h

+// Copyright 2016 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.
+
+#ifndef CHROME_BROWSER_UI_STARTUP_DEFAULT_BROWSER_INFOBAR_DELEGATE_H_
+#define CHROME_BROWSER_UI_STARTUP_DEFAULT_BROWSER_INFOBAR_DELEGATE_H_
+
+#include "base/feature_list.h"
+#include "chrome/browser/infobars/infobar_service.h"
+#include "chrome/browser/shell_integration.h"
+#include "components/infobars/core/confirm_infobar_delegate.h"
+
+class Profile;
+
+namespace chrome {
+
+// The StickyDefaultBrowserPrompt experiment delays the dismissal of the
+// DefaultBrowserPrompt to after a change in the default browser setting has
+// been detected.
+extern const base::Feature kStickyDefaultBrowserPrompt;

[Peter Kasting, 2016/06/01 00:21:12]

Is it possible to declare this as non-extern constexpr by putting the definition
here?  Or does that lead to ODR violations?  (I'm not sure how the compiler
handles constexpr aggregates in headers w.r.t. emitting definitions.)

[Patrick Monette, 2016/06/01 18:43:48]

Seems to work. Done.

+
+// Returns true if the StickyDefaultBrowserPrompt experiment is enabled.
+bool IsStickyDefaultBrowserPromptEnabled();
+
+// 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.
+class DefaultBrowserInfoBarDelegate : public ConfirmInfoBarDelegate {
+ public:
+  // Creates a default browser infobar and delegate and adds the infobar to
+  // |infobar_service|.
+  static void Create(InfoBarService* infobar_service, Profile* profile);
+
+ protected:
+  explicit DefaultBrowserInfoBarDelegate(Profile* profile);
+  ~DefaultBrowserInfoBarDelegate() override;
+
+ private:
+  // Possible user interactions with the default browser info bar.
+  // Do not modify the ordering as it is important for UMA.
+  enum InfoBarUserInteraction {
+    // The user clicked the "OK" (i.e., "Set as default") button.
+    ACCEPT_INFO_BAR = 0,
+    // The user clicked the "Cancel" (i.e., "Don't ask again") button.
+    CANCEL_INFO_BAR = 1,
+    // The user did not interact with the info bar.
+    IGNORE_INFO_BAR = 2,
+    NUM_INFO_BAR_USER_INTERACTION_TYPES
+  };
+
+  void AllowExpiry() { should_expire_ = true; }

[Peter Kasting, 2016/06/01 00:21:12]

Nit: If you want to inline this, name it unix_hacker()-style; otherwise deinline
the body.

[Patrick Monette, 2016/06/01 18:43:48]

Moved the definition to the .cc file.

[Peter Kasting, 2016/06/01 19:32:10]

I don't see that...

[Patrick Monette, 2016/06/01 22:07:39]

Now moved.

+
+  // InfoBarDelegate:

[Peter Kasting, 2016/06/01 00:21:12]

Nit: This class doesn't directly subclass InfoBarDelegate.  These should be
included atop the ConfirmInfoBarDelegate list.

[Patrick Monette, 2016/06/01 18:43:48]

Done.

+  Type GetInfoBarType() const override;
+  infobars::InfoBarDelegate::InfoBarIdentifier GetIdentifier() const override;
+  int GetIconId() const override;
+  gfx::VectorIconId GetVectorIconId() const override;
+  bool ShouldExpire(const NavigationDetails& details) const override;
+  void InfoBarDismissed() override;
+
+  // ConfirmInfoBarDelegate:
+  base::string16 GetMessageText() const override;
+  base::string16 GetButtonLabel(InfoBarButton button) const override;
+  bool OKButtonTriggersUACPrompt() const override;
+  bool Accept() override;
+  bool Cancel() override;
+
+  virtual scoped_refptr<shell_integration::DefaultBrowserWorker>

[Peter Kasting, 2016/06/01 00:21:11]

Nit: Perhaps note "Declared virtual so tests can override."

[Patrick Monette, 2016/06/01 18:43:48]

Done.

+  CreateDefaultBrowserWorker(
+      const shell_integration::DefaultWebClientWorkerCallback& callback);
+
+  // Removes the infobar when the worker is finished setting the default
+  // browser. Only used if the StickyDefaultBrowserPrompt experiment is
+  // enabled.
+  void OnSetAsDefaultFinished(shell_integration::DefaultWebClientState state);
+
+  // The WebContents's corresponding profile.
+  Profile* profile_;
+
+  scoped_refptr<base::SingleThreadTaskRunner> thread_task_runner_;
+
+  // Whether the info-bar should be dismissed on the next navigation.

[Peter Kasting, 2016/06/01 00:21:12]

Nit: No hyphen

[Patrick Monette, 2016/06/01 18:43:48]

Done.

+  bool should_expire_ = false;

[Peter Kasting, 2016/06/01 00:21:12]

Nit: Since you initialize everything else in the initializer list, I would do
this there as well.

[Patrick Monette, 2016/06/01 18:43:48]

Done.

+
+  // Used to delay the expiration of the info-bar.
+  base::WeakPtrFactory<DefaultBrowserInfoBarDelegate> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(DefaultBrowserInfoBarDelegate);
+};
+
+}  // namespace chrome
+
+#endif  // CHROME_BROWSER_UI_STARTUP_DEFAULT_BROWSER_INFOBAR_DELEGATE_H_