Fixed NavigationItemImpl::GetDisplayTitleForURL for 'file://' URL.

Use full URL spec if it ends with /

BUG=719982

Review-Url: https://codereview.chromium.org/2876053002
Cr-Commit-Position: refs/heads/master@{#471105}

ios/web/navigation/navigation_item_impl.mm

@@ -297,7 +297,7 @@ base::string16 NavigationItemImpl::GetDisplayTitleForURL(const GURL& url) {
   // For file:// URLs use the filename as the title, not the full path.
   if (url.SchemeIsFile()) {
     base::string16::size_type slashpos = title.rfind('/');
-    if (slashpos != base::string16::npos)
+    if (slashpos != base::string16::npos && slashpos != (title.size() - 1))
       title = title.substr(slashpos + 1);
   }
 

ios/web/navigation/navigation_item_impl_unittest.mm

@@ -148,5 +148,19 @@ TEST_F(NavigationItemTest, VirtualURLTest) {
   EXPECT_EQ(original_url, item_->GetURL());
 }
 
+// Tests NavigationItemImpl::GetDisplayTitleForURL method.
+TEST_F(NavigationItemTest, GetDisplayTitleForURL) {
+  base::string16 title;
+
+  title = NavigationItemImpl::GetDisplayTitleForURL(GURL("http://foo.org/"));
+  EXPECT_EQ("foo.org", base::UTF16ToUTF8(title));
+
+  title = NavigationItemImpl::GetDisplayTitleForURL(GURL("file://foo.org/"));
+  EXPECT_EQ("file://foo.org/", base::UTF16ToUTF8(title));
+
+  title = NavigationItemImpl::GetDisplayTitleForURL(GURL("file://foo/1.gz"));
+  EXPECT_EQ("1.gz", base::UTF16ToUTF8(title));
+}
+
 }  // namespace
 }  // namespace web