Convert NavigationEntry title to string16. TabContents::GetTitle no longer needs

to be virtual, either.

This also changes how the display URL is computed. Instead of doing it
preemptively, we now do so lazily. This allows us to do the URL formatting
correctly using the elider so that we can do IDN and unescaping.

I changed string_util's singleton functions. I was worried that other code
might make a singleton of string, which would give you this same value as a
non-const string. This would mean our empty strings might no longer be empty.
Review URL: http://codereview.chromium.org/39022

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@10872 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 17 insertions, 2 deletions

diff --git a/base/string_util.cc b/base/string_util.cc
index a13f79f..8f9bcf9 100644
--- a/base/string_util.cc
+++ b/base/string_util.cc
@@ -27,6 +27,16 @@
 
 namespace {
 
+// Force the singleton used by Empty[W]String[16] to be a unique type. This
+// prevents other code that might accidentally use Singleton<string> from
+// getting our internal one.
+struct EmptyStrings {
+  EmptyStrings() {}
+  const std::string s;
+  const std::wstring ws;
+  const string16 s16;
+};
+
 // Hack to convert any char-like type to its unsigned counterpart.
 // For example, it will convert char, signed char and unsigned char to unsigned
 // char.
@@ -323,11 +333,15 @@ bool IsWprintfFormatPortable(const wchar_t* format) {
 
 
 const std::string& EmptyString() {
-  return *Singleton<std::string>::get();
+  return Singleton<EmptyStrings>::get()->s;
 }
 
 const std::wstring& EmptyWString() {
-  return *Singleton<std::wstring>::get();
+  return Singleton<EmptyStrings>::get()->ws;
+}
+
+const string16& EmptyString16() {
+  return Singleton<EmptyStrings>::get()->s16;
 }
 
 const wchar_t kWhitespaceWide[] = {
diff --git a/base/string_util.h b/base/string_util.h
index 1247cd5..3f905fe 100644
--- a/base/string_util.h
+++ b/base/string_util.h
@@ -112,6 +112,7 @@ bool IsWprintfFormatPortable(const wchar_t* format);
 // These functions are threadsafe.
 const std::string& EmptyString();
 const std::wstring& EmptyWString();
+const string16& EmptyString16();
 
 extern const wchar_t kWhitespaceWide[];
 extern const char kWhitespaceASCII[];