Open from clipboard: Support nil clipboard

Starting with iOS9 beta 5, the clipboard string can be nil in some
circonstances.
Consider this as a temporary access error and not a pasteboard change.

Review URL: https://codereview.chromium.org/1293693006

Cr-Commit-Position: refs/heads/master@{#343648}

1 files changed, 15 insertions, 10 deletions

diff --git a/components/open_from_clipboard/clipboard_recent_content_ios.mm b/components/open_from_clipboard/clipboard_recent_content_ios.mm
index 7665e46..123c4aa 100644
--- a/components/open_from_clipboard/clipboard_recent_content_ios.mm
+++ b/components/open_from_clipboard/clipboard_recent_content_ios.mm
@@ -148,6 +148,9 @@ void ClipboardRecentContentIOS::SuppressClipboardContent() {
 }
 
 void ClipboardRecentContentIOS::PasteboardChanged() {
+  NSString* pasteboard_string = [[UIPasteboard generalPasteboard] string];
+  if (!pasteboard_string)
+    return;
   url_from_pasteboard_cache_ = URLFromPasteboard();
   if (!url_from_pasteboard_cache_.is_empty()) {
     base::RecordAction(
@@ -155,10 +158,6 @@ void ClipboardRecentContentIOS::PasteboardChanged() {
   }
   last_pasteboard_change_date_.reset([[NSDate date] retain]);
   last_pasteboard_change_count_ = [UIPasteboard generalPasteboard].changeCount;
-  NSString* pasteboard_string = [[UIPasteboard generalPasteboard] string];
-  if (!pasteboard_string) {
-    pasteboard_string = @"";
-  }
   NSData* MD5 = WeakMD5FromNSString(pasteboard_string);
   last_pasteboard_entry_md5_.reset([MD5 retain]);
   SaveToUserDefaults();
@@ -181,6 +180,13 @@ ClipboardRecentContentIOS::ClipboardRecentContentIOS(
 }
 
 bool ClipboardRecentContentIOS::HasPasteboardChanged(base::TimeDelta uptime) {
+  // If [[UIPasteboard generalPasteboard] string] is nil, the content of the
+  // pasteboard cannot be accessed. This case should not be considered as a
+  // pasteboard change.
+  NSString* pasteboard_string = [[UIPasteboard generalPasteboard] string];
+  if (!pasteboard_string)
+    return NO;
+
   // If |MD5Changed|, we know for sure there has been at least one pasteboard
   // copy since last time it was checked.
   // If the pasteboard content is still the same but the device was not
@@ -196,10 +202,6 @@ bool ClipboardRecentContentIOS::HasPasteboardChanged(base::TimeDelta uptime) {
   if (not_rebooted)
     return change_count_changed;
 
-  NSString* pasteboard_string = [[UIPasteboard generalPasteboard] string];
-  if (!pasteboard_string) {
-    pasteboard_string = @"";
-  }
   NSData* md5 = WeakMD5FromNSString(pasteboard_string);
   BOOL md5_changed = ![md5 isEqualToData:last_pasteboard_entry_md5_];
 
@@ -225,8 +227,11 @@ ClipboardRecentContentIOS::~ClipboardRecentContentIOS() {
 }
 
 GURL ClipboardRecentContentIOS::URLFromPasteboard() {
-  const std::string clipboard =
-      base::SysNSStringToUTF8([[UIPasteboard generalPasteboard] string]);
+  NSString* clipboard_string = [[UIPasteboard generalPasteboard] string];
+  if (!clipboard_string) {
+    return GURL::EmptyGURL();
+  }
+  const std::string clipboard = base::SysNSStringToUTF8(clipboard_string);
   GURL gurl = GURL(clipboard);
   if (gurl.is_valid()) {
     for (size_t i = 0; i < arraysize(kAuthorizedSchemes); ++i) {