Improvements to tab title prefix eliding as per email discussions.

chrome/browser/ui/views/tabs/base_tab.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/views/tabs/base_tab.h"
 
 #include <limits>
 
 #include "base/command_line.h"
 #include "base/utf_string_conversions.h"
@@ skipping 461 matching lines @@
   const gfx::Rect& title_bounds = GetTitleBounds();
   string16 title = data().title;
   if (title.empty()) {
     title = data().loading ?
         l10n_util::GetStringUTF16(IDS_TAB_LOADING_TITLE) :
         TabContentsWrapper::GetDefaultTitle();
   } else {
     Browser::FormatTitleForDisplay(&title);
     // If we'll need to truncate, check if we should also truncate
     // a common prefix, but only if there is enough room for it.
-    // We arbitrarily choose to request enough room for 10 average chars.
-    if (data().common_prefix_length > 0 &&
-        font_->GetExpectedTextWidth(10) < title_bounds.width() &&
+    // We arbitrarily choose to request enough room for 6 average chars.
+    // Also, we want to show the last 4 common chars, so we only do it if
+    // the common prefix is at least 7 characters long, otherwise, we would be
+    // replacing 3 or less characters with a 3 dot ellipsis... not worth it.
+    if (data().common_prefix_length > 7 &&
+        font_->GetExpectedTextWidth(6) < title_bounds.width() &&
         font_->GetStringWidth(title) > title_bounds.width()) {
-      title.replace(0, data().common_prefix_length, UTF8ToUTF16(ui::kEllipsis));
+      title.replace(0, data().common_prefix_length - 4,
+                    UTF8ToUTF16(ui::kEllipsis));
     }
   }
   canvas->DrawStringInt(title, *font_, title_color,
                         title_bounds.x(), title_bounds.y(),
                         title_bounds.width(), title_bounds.height());
 }
 
 void BaseTab::AnimationProgressed(const ui::Animation* animation) {
   SchedulePaint();
 }
@@ skipping 76 matching lines @@
 // static
 void BaseTab::InitResources() {
   static bool initialized = false;
   if (!initialized) {
     initialized = true;
     font_ = new gfx::Font(
         ResourceBundle::GetSharedInstance().GetFont(ResourceBundle::BaseFont));
     font_height_ = font_->GetHeight();
   }
 }