Got the about panel to have its text lined up correctly.

app/gfx/font_skia.cc

 // Copyright (c) 2006-2008 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 "app/gfx/font.h"
 
 #include <gdk/gdk.h>
+#include <map>
 #include <pango/pango.h>
 
 #include "app/gfx/canvas.h"
 #include "base/logging.h"
 #include "base/string_piece.h"
 #include "base/sys_string_conversions.h"
 #include "third_party/skia/include/core/SkTypeface.h"
 #include "third_party/skia/include/core/SkPaint.h"
 
 namespace {
@@ skipping 17 matching lines @@
     scale_factor = pango_cairo_context_get_resolution(context);
     g_object_unref(context);
     if (scale_factor <= 0)
       scale_factor = 1;
     else
       scale_factor /= 72.0;
   }
   return scale_factor;
 }
 
+// Retrieves the pango metrics for a pango font description. Caches the metrics
+// and never frees them. The metrics objects are relatively small and
+// very expensive to look up.
+static PangoFontMetrics* GetPangoFontMetrics(PangoFontDescription* desc) {
+  static std::map<int, PangoFontMetrics*>* desc_to_metrics = NULL;
+  static PangoContext* context = NULL;
+
+  if (!context) {
+    context = gdk_pango_context_get_for_screen(gdk_screen_get_default());
+    pango_context_set_language(context, pango_language_get_default());
+  }
+
+  if (!desc_to_metrics) {
+    desc_to_metrics = new std::map<int, PangoFontMetrics*>();
+  }
+
+  int desc_hash = pango_font_description_hash(desc);
+  std::map<int, PangoFontMetrics*>::iterator i =
+      desc_to_metrics->find(desc_hash);
+
+  if (i == desc_to_metrics->end()) {
+    PangoFontMetrics* metrics = pango_context_get_metrics(context, desc, NULL);
+    (*desc_to_metrics)[desc_hash] = metrics;
+    return metrics;
+  } else {
+    return i->second;
+  }
+}
+
 }  // namespace
 
 namespace gfx {
 
 Font::Font(const Font& other) {
   CopyFont(other);
 }
 
 Font& Font::operator=(const Font& other) {
   CopyFont(other);
   return *this;
 }
 
 Font::Font(SkTypeface* tf, const std::wstring& font_family, int font_size,
            int style)
     : typeface_helper_(new SkAutoUnref(tf)),
       typeface_(tf),
       font_family_(font_family),
       font_size_(font_size),
-      style_(style) {
+      style_(style),
+      pango_metrics_inited_(false),
+      avg_width_(0.0),
+      underline_position_(0.0),
+      underline_thickness_(0.0) {
   tf->ref();
   calculateMetrics();
 }
 
 void Font::calculateMetrics() {
   SkPaint paint;
   SkPaint::FontMetrics metrics;
   PaintSetup(&paint);
   paint.getFontMetrics(&metrics);
 
   ascent_ = SkScalarCeil(-metrics.fAscent);
   height_ = ascent_ + SkScalarCeil(metrics.fDescent);
-  // avg_width_ is calculated lazily, as it's expensive and not used often.
-  avg_width_ = -1.0;
 
 }
 
 void Font::CopyFont(const Font& other) {
   typeface_helper_.reset(new SkAutoUnref(other.typeface_));
   typeface_ = other.typeface_;
   typeface_->ref();
   font_family_ = other.font_family_;
   font_size_ = other.font_size_;
   style_ = other.style_;
   height_ = other.height_;
   ascent_ = other.ascent_;
+  pango_metrics_inited_ = other.pango_metrics_inited_;
   avg_width_ = other.avg_width_;
+  underline_position_ = other.underline_position_;
+  underline_thickness_ = other.underline_thickness_;
 }
 
 int Font::height() const {
   return height_;
 }
 
 int Font::baseline() const {
   return ascent_;
 }
 
 int Font::ave_char_width() const {
-  return SkScalarRound(const_cast<Font*>(this)->avg_width());
+  return SkScalarRound(avg_width());
 }
 
 Font Font::CreateFont(const std::wstring& font_family, int font_size) {
   DCHECK_GT(font_size, 0);
   std::wstring fallback;
 
   SkTypeface* tf = SkTypeface::CreateFromName(
       base::SysWideToUTF8(font_family).c_str(), SkTypeface::kNormal);
   if (!tf) {
     // A non-scalable font such as .pcf is specified. Falls back to a default
@@ skipping 27 matching lines @@
   if (BOLD & style)
     skstyle |= SkTypeface::kBold;
   if (ITALIC & style)
     skstyle |= SkTypeface::kItalic;
 
   SkTypeface* tf = SkTypeface::CreateFromName(
       base::SysWideToUTF8(font_family_).c_str(),
       static_cast<SkTypeface::Style>(skstyle));
   SkAutoUnref tf_helper(tf);
 
-  return Font(tf, font_family_, font_size_ + size_delta, skstyle);
+  return Font(tf, font_family_, font_size_ + size_delta, style);
 }
 
 void Font::PaintSetup(SkPaint* paint) const {
   paint->setAntiAlias(false);
   paint->setSubpixelText(false);
   paint->setTextSize(SkFloatToScalar(font_size_ * GetPangoScaleFactor()));
   paint->setTypeface(typeface_);
   paint->setFakeBoldText((BOLD & style_) && !typeface_->isBold());
   paint->setTextSkewX((ITALIC & style_) && !typeface_->isItalic() ?
                       -SK_Scalar1/4 : 0);
 }
 
 int Font::GetStringWidth(const std::wstring& text) const {
   int width = 0, height = 0;
 
   Canvas::SizeStringInt(text, *this, &width, &height, 0);
   return width;
 }
 
-double Font::avg_width() {
-  if (avg_width_ < 0) {
+void Font::InitPangoMetrics() {
+  if (!pango_metrics_inited_) {
+    pango_metrics_inited_ = true;
+    PangoFontDescription* pango_desc = PangoFontFromGfxFont(*this);
+    PangoFontMetrics* pango_metrics = GetPangoFontMetrics(pango_desc);
+
+    underline_position_ =
+        pango_font_metrics_get_underline_position(pango_metrics);
+    underline_position_ /= PANGO_SCALE;
+
+    // todo(davemoore) Come up with a better solution.
+    // This is a hack, but without doing this the underlines
+    // we get end up fuzzy. So we align to the midpoint of a pixel.
+    underline_position_ /= 2;
+
+    underline_thickness_ =
+        pango_font_metrics_get_underline_thickness(pango_metrics);
+    underline_thickness_ /= PANGO_SCALE;
+
     // First get the pango based width
-    PangoFontDescription* pango_desc = PangoFontFromGfxFont(*this);
-    PangoContext* context =
-        gdk_pango_context_get_for_screen(gdk_screen_get_default());
-    PangoFontMetrics* pango_metrics =
-        pango_context_get_metrics(context,
-                                  pango_desc,
-                                  pango_language_get_default());
     double pango_width =
         pango_font_metrics_get_approximate_char_width(pango_metrics);
     pango_width /= PANGO_SCALE;
 
     // Yes, this is how Microsoft recommends calculating the dialog unit
     // conversions.
     int text_width = GetStringWidth(
         L"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz");
     double dialog_units = (text_width / 26 + 1) / 2;
     avg_width_ = std::min(pango_width, dialog_units);
-    pango_font_metrics_unref(pango_metrics);
     pango_font_description_free(pango_desc);
   }
+}
+
+double Font::avg_width() const {
+  const_cast<Font*>(this)->InitPangoMetrics();
   return avg_width_;
 }
 
+double Font::underline_position() const {
+  const_cast<Font*>(this)->InitPangoMetrics();
+  return underline_position_;
+}
+
+double Font::underline_thickness() const {
+  const_cast<Font*>(this)->InitPangoMetrics();
+  return underline_thickness_;
+}
+
 int Font::GetExpectedTextWidth(int length) const {
   double char_width = const_cast<Font*>(this)->avg_width();
   return round(static_cast<float>(length) * char_width);
 }
 
 int Font::style() const {
   return style_;
 }
 
 std::wstring Font::FontName() {
   return font_family_;
 }
 
 int Font::FontSize() {
   return font_size_;
 }
 
 NativeFont Font::nativeFont() const {
   return typeface_;
 }
 
 }  // namespace gfx