Open from clipboard: Support nil clipboard

components/open_from_clipboard/clipboard_recent_content_ios.mm

Index: components/open_from_clipboard/clipboard_recent_content_ios.mm
diff --git a/components/open_from_clipboard/clipboard_recent_content_ios.mm b/components/open_from_clipboard/clipboard_recent_content_ios.mm
index 7665e46731dd30992369991cabd68b0035c3ae39..123c4aa5afd4287356e2bec0c02aec567884d80c 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);

[droger, 2015/08/17 08:27:39]

It seems this change does not affect the behavior of the function. Is it a
mistake?

[Olivier, 2015/08/17 08:33:19]

The result is the same.
But adding the early return avoid testing the schemes and 
If [[UIPasteboard generalPasteboard] string] is nil, we should do at little as
possible, and specially not update the stored entries in NSUserDefaults.
Adding an early return will also avoid mistakes if something is added to the
function.

   GURL gurl = GURL(clipboard);
   if (gurl.is_valid()) {
     for (size_t i = 0; i < arraysize(kAuthorizedSchemes); ++i) {