Picker takes a vector of pairs, and passes back the user chosen target.

chrome/browser/webshare/share_service_impl.h

Index: chrome/browser/webshare/share_service_impl.h
diff --git a/chrome/browser/webshare/share_service_impl.h b/chrome/browser/webshare/share_service_impl.h
index bcc2a5575544da2e6dd01c0c0d4a2a1b935206f1..0a3cecf656830184fd1a447ae93483386ee5f694 100644
--- a/chrome/browser/webshare/share_service_impl.h
+++ b/chrome/browser/webshare/share_service_impl.h
@@ -14,11 +14,6 @@
 
 class GURL;
 
-enum class SharePickerResult {
-  CANCEL,
-  SHARE
-};
-
 // Desktop implementation of the ShareService Mojo service.
 class ShareServiceImpl : public blink::mojom::ShareService {
  public:
@@ -37,11 +32,12 @@ class ShareServiceImpl : public blink::mojom::ShareService {
   FRIEND_TEST_ALL_PREFIXES(ShareServiceImplUnittest, ReplacePlaceholders);
 
   // Shows the share picker dialog with |targets| as the list of applications
-  // presented to the user. Passes the result to |callback|. Virtual for
-  // testing.
+  // presented to the user. Passes the result to |callback|. If the user picks a
+  // target, the result passed to |callback| is the manifest URL of the chosen
+  // target, and is null if the user cancelled the share. Virtual for testing.

[Matt Giuca, 2017/02/01 07:04:33]

s/and/or :)

[constantina, 2017/02/01 23:24:21]

Done :)

   virtual void ShowPickerDialog(
       const std::vector<base::string16>& targets,
-      const base::Callback<void(SharePickerResult)>& callback);
+      const base::Callback<void(base::Optional<base::string16>)>& callback);
 
   // Opens a new tab and navigates to |target_url|.
   // Virtual for testing purposes.
@@ -65,7 +61,7 @@ class ShareServiceImpl : public blink::mojom::ShareService {
                       const std::string& text,
                       const GURL& share_url,
                       const ShareCallback& callback,
-                      SharePickerResult result);
+                      base::Optional<base::string16> result);
 
   DISALLOW_COPY_AND_ASSIGN(ShareServiceImpl);
 };