Add chrome.hid.getUserSelectedDevices API.

chrome/browser/ui/cocoa/extensions/device_permissions_dialog_controller.mm

Index: chrome/browser/ui/cocoa/extensions/device_permissions_dialog_controller.mm
diff --git a/chrome/browser/ui/cocoa/extensions/device_permissions_dialog_controller.mm b/chrome/browser/ui/cocoa/extensions/device_permissions_dialog_controller.mm
index a83697202296b9bc133867d4522ade3d5ca4528c..8808abd43050dd4fbc710275079edd26ecba31ed 100644
--- a/chrome/browser/ui/cocoa/extensions/device_permissions_dialog_controller.mm
+++ b/chrome/browser/ui/cocoa/extensions/device_permissions_dialog_controller.mm
@@ -12,6 +12,7 @@
 #import "chrome/browser/ui/cocoa/constrained_window/constrained_window_custom_sheet.h"
 #import "chrome/browser/ui/cocoa/constrained_window/constrained_window_custom_window.h"
 #import "chrome/browser/ui/cocoa/extensions/device_permissions_view_controller.h"
+#include "components/web_modal/web_contents_modal_dialog_manager.h"
 #include "device/usb/usb_device.h"
 
 using extensions::DevicePermissionsPrompt;
@@ -55,6 +56,12 @@ void DevicePermissionsDialogController::OnConstrainedWindowClosed(
 }
 
 void ChromeDevicePermissionsPrompt::ShowDialog() {
-  // These objects will delete themselves when the dialog closes.
-  new DevicePermissionsDialogController(web_contents(), prompt());
+  web_modal::WebContentsModalDialogManager* manager =
+      web_modal::WebContentsModalDialogManager::FromWebContents(web_contents());
+  if (manager) {
+    // These objects will delete themselves when the dialog closes.
+    new DevicePermissionsDialogController(web_contents(), prompt());
+  } else {
+    prompt()->Dismissed();

[Devlin, 2015/05/14 17:38:11]

- Can we consolidate this code with the views equivalent in the base class
somehow?
- Is treating the prompt as Dismissed() the right this to do in this case?  Or
should we instead indicate that it was never shown?  (Even though for the API,
the result might be the same, if we ever wanna show this prompt again, it might
be good to be able to differentiate).
- Calling dismissed synchronously like this is problematic (see comments in
api.cc).

[Reilly Grant (use Gerrit), 2015/05/14 18:04:28]

The modal dialog managers seem to work slightly differently so I don't think
they can be consolidated. I'll push the failure handling up into the parent
class.

[Devlin, 2015/05/14 18:32:02]

And you're confident that Dismissed()'ing the dialog is the right thing to do,
even if it never showed?  (You didn't respond to this in your comment.)

+  }
 }