Elide long emails in the wrench and profile menus.

ui/base/text/text_elider.cc

Index: ui/base/text/text_elider.cc
diff --git a/ui/base/text/text_elider.cc b/ui/base/text/text_elider.cc
index 525cea0df61eb373507b91372f144dbf327cf419..917cefda2a574ac378af26b01f1ce5e912b116db 100644
--- a/ui/base/text/text_elider.cc
+++ b/ui/base/text/text_elider.cc
@@ -149,12 +149,53 @@ string16 ElideComponentizedPath(const string16& url_path_prefix,
 
 }  // namespace
 
-// This function takes a GURL object and elides it. It returns a string
-// which composed of parts from subdomain, domain, path, filename and query.
-// A "..." is added automatically at the end if the elided string is bigger
-// than the available pixel width. For available pixel width = 0, a formatted,
-// but un-elided, string is returned.
-//
+string16 ElideEmail(const string16& email,
+                    const gfx::Font& font,
+                    int available_pixel_width) {
+  if (font.GetStringWidth(email) <= available_pixel_width)
+    return email;
+
+  std::vector<string16> email_split;
+  base::SplitString(email, '@', &email_split);
+  DCHECK_EQ(email_split.size(), 2U);
+  string16 username = email_split.front();
+  string16 domain = email_split.back();

[gab, 2012/03/01 19:37:25]

@asvitkine: I remember you said you prefer string16 to string16& here, but that
forces an unnecessary string copy. Are we okay with that tiny performance loss?

[asvitkine_google, 2012/03/01 20:13:29]

This is fine. The run time will be dominated by calls to GetStringWidth(),
rather than the cost of copying a few dozen characters.

+
+  const string16 kEllipsisUTF16 = UTF8ToUTF16(kEllipsis);
+  const int kEllipsisSize = font.GetStringWidth(kEllipsisUTF16);

[asvitkine_google, 2012/03/01 20:13:29]

Please rename all the variables that end in Size or _size to use "width"
instead, so that it's clearer that they refer to string widths.

+
+  // Ignore the @ symbol and add it back at the end.
+  const string16 kAtSignUTF16 = ASCIIToUTF16("@");
+  available_pixel_width -= font.GetStringWidth(kAtSignUTF16);
+
+  // Reserve characters for each of: username ellipsis, @ symbol, and at least
+  // one character remaining in the username.

[asvitkine_google, 2012/03/01 20:13:29]

I would comment this slightly differently - have the comment mention why it's
doing this, i.e. to explain you're checking whether the domain name needs to be
elided, which is true only if it doesn't fit when the username is fully elided.

+  const int available_domain_size = available_pixel_width -
+                                    kEllipsisSize -
+                                    font.GetStringWidth(username.substr(0, 1));

[asvitkine_google, 2012/03/01 20:13:29]

Please use font.GetStringWidth(username.substr(0, 1) + kEllipsisUTF16), since
it's not guaranteed that it equals the sum of the individual widths.

+  const int full_username_size = font.GetStringWidth(username);
+  if (font.GetStringWidth(domain) > available_domain_size) {
+    const int desired_domain_size =
+        std::max(available_pixel_width - full_username_size,

[asvitkine_google, 2012/03/01 20:13:29]

Please comment the logic behind this.

[gab, 2012/03/01 21:48:18]

I was trying to be less verbose by leaving all the description in the method
header comment, this addresses this part of the method spec: "(should the
username be short enough that it doesn't require half the available width: the
domain will take that extra width)."

I added a comment inline that explains this in more details. Let me know what
you prefer.

+                 available_pixel_width / 2);
+    domain = ElideText(domain, font, desired_domain_size, ELIDE_IN_MIDDLE);
+    if (domain.length() <= 1U)
+      return kEllipsisUTF16;
+  }
+
+  const int final_domain_size = font.GetStringWidth(domain);
+  if (full_username_size + final_domain_size > available_pixel_width) {
+    username = ElideText(username,
+                         font,
+                         available_pixel_width - final_domain_size,
+                         ELIDE_AT_END);
+    if (username.length() <= 1U)
+      return kEllipsisUTF16;
+  }
+
+  return username + kAtSignUTF16 + domain;
+}
+
 // TODO(pkasting): http://crbug.com/77883 This whole function gets
 // kerning/ligatures/etc. issues potentially wrong by assuming that the width of
 // a rendered string is always the sum of the widths of its substrings.  Also I
@@ -393,8 +434,6 @@ string16 ElideFilename(const FilePath& filename,
   return base::i18n::GetDisplayStringInLTRDirectionality(elided_name);
 }
 
-// This function adds an ellipsis at the end of the text if the text
-// does not fit the given pixel width.
 string16 ElideText(const string16& text,
                    const gfx::Font& font,
                    int available_pixel_width,