webshare: Small refactor of WebShare (OnceCallback, const&, and alias)

chrome/browser/ui/browser_dialogs.h

 // Copyright (c) 2012 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_BROWSER_DIALOGS_H_
 #define CHROME_BROWSER_UI_BROWSER_DIALOGS_H_
 
 #include <string>
 #include <utility>
 #include <vector>
@@ skipping 55 matching lines @@
 namespace task_manager {
 class TaskManagerTableModel;
 }
 
 namespace ui {
 class WebDialogDelegate;
 }
 
 namespace chrome {
 
+// Used by ShowWebShareTargetPickerDialog to return the target the user picked
+// or nullopt if the user cancelled the share.
+using WebShareTargetPickerCallback =
+    base::Callback<void(const base::Optional<std::string>&)>;

[Matt Giuca, 2017/05/01 06:50:06]

I think this should go at the bottom of the file -- see how there is a similar
one called IntentPickerResponse. Just make sure it goes outside of the ifdef
CHROMEOS.

[ortuno, 2017/05/01 07:13:02]

As discussed the alias has to be defined before it's used i.e. before
ShowWebShareTargetPickerDialog.

[sky, 2017/05/01 21:08:50]

optional: put this right above the the single place it's used.
optional2: use OnceCallback.

[ortuno, 2017/05/01 22:55:00]

Done. Q: Is it usually just a judgement call where to put the alias? The style
guide says to put it at the top of the file with other types[1] but I've seen
instances of them being defined right above where they are used[2].
Done.

[1] https://google.github.io/styleguide/cppguide.html#Declaration_Order
[2]
https://cs.chromium.org/chromium/src/device/bluetooth/bluetooth_device.h?sq=p...

+
 // Shows or hides the Task Manager. |browser| can be NULL when called from Ash.
 // Returns a pointer to the underlying TableModel, which can be ignored, or used
 // for testing.
 task_manager::TaskManagerTableModel* ShowTaskManager(Browser* browser);
 void HideTaskManager();
 
 #if !defined(OS_MACOSX)
 // Creates and shows an HTML dialog with the given delegate and context.
 // The window is automatically destroyed when it is closed.
 // Returns the created window.
@@ skipping 71 matching lines @@
 payments::PaymentRequestDialog* CreatePaymentRequestDialog(
     payments::PaymentRequest* request);
 
 // Shows the dialog to choose a share target app. |targets| is a list of app
 // title and manifest URL pairs that will be shown in a list. If the user picks
 // a target, this calls |callback| with the manifest URL of the chosen target,
 // or supplies null if the user cancelled the share.
 void ShowWebShareTargetPickerDialog(
     gfx::NativeWindow parent_window,
     const std::vector<std::pair<base::string16, GURL>>& targets,
-    const base::Callback<void(base::Optional<std::string>)>& callback);
+    const WebShareTargetPickerCallback& callback);
 
 #if defined(OS_MACOSX)
 
 // This is a class so that it can be friended from ContentSettingBubbleContents,
 // which allows it to call SetAnchorRect().
 class ContentSettingBubbleViewsBridge {
  public:
   static void Show(gfx::NativeView parent_view,
                    ContentSettingBubbleModel* model,
                    content::WebContents* web_contents,
@@ skipping 71 matching lines @@
 using BubbleShowPtr =
     void (*)(content::WebContents*,
              const std::vector<arc::ArcNavigationThrottle::AppInfo>&,
              const IntentPickerResponse&);
 
 BubbleShowPtr ShowIntentPickerBubble();
 
 #endif  // OS_CHROMEOS
 
 #endif  // CHROME_BROWSER_UI_BROWSER_DIALOGS_H_