Ensure that text with leading, trailing and interspersed tabs pasted into the textfield

ui/views/controls/textfield/textfield_model.cc

Index: ui/views/controls/textfield/textfield_model.cc
diff --git a/ui/views/controls/textfield/textfield_model.cc b/ui/views/controls/textfield/textfield_model.cc
index d270a20c0a01e8cbcaddd8a6949f208e33dd6e26..6b17c5c69d10a58c9b1ea82a90e8a1850770e917 100644
--- a/ui/views/controls/textfield/textfield_model.cc
+++ b/ui/views/controls/textfield/textfield_model.cc
@@ -8,6 +8,8 @@
 
 #include "base/logging.h"
 #include "base/stl_util.h"
+#include "base/strings/string_util.h"
+#include "base/strings/utf_string_conversions.h"
 #include "ui/base/clipboard/clipboard.h"
 #include "ui/base/clipboard/scoped_clipboard_writer.h"
 #include "ui/gfx/range/range.h"
@@ -509,13 +511,18 @@ bool TextfieldModel::Copy() {
 }
 
 bool TextfieldModel::Paste() {
-  base::string16 result;
+  base::string16 text;
   ui::Clipboard::GetForCurrentThread()->ReadText(ui::CLIPBOARD_TYPE_COPY_PASTE,
-                                                 &result);
-  if (result.empty())
+                                                 &text);
+  if (text.empty())
     return false;
 
-  InsertTextInternal(result, false);
+  base::string16 actual_text = base::CollapseWhitespace(text, false);
+  // If the clipboard contains all whitespaces then paste a single space.
+  if (actual_text.empty())
+    actual_text = base::ASCIIToUTF16(" ");
+
+  InsertTextInternal(actual_text, false);
   return true;
 }