Get all font unittests running with DirectWrite on Windows 7+

ui/gfx/platform_font_win.cc

Index: ui/gfx/platform_font_win.cc
diff --git a/ui/gfx/platform_font_win.cc b/ui/gfx/platform_font_win.cc
index 5e9d2537e5a188d88bf8b1bd186c36b50376a954..769c17388e12d11f3829d9856e3e52277b3ecf24 100644
--- a/ui/gfx/platform_font_win.cc
+++ b/ui/gfx/platform_font_win.cc
@@ -211,14 +211,20 @@ PlatformFontWin::PlatformFontWin(const std::string& font_name,
 
 Font PlatformFontWin::DeriveFontWithHeight(int height, int style) {
   DCHECK_GE(height, 0);
-  if (GetHeight() == height && GetStyle() == style)
-    return Font(this);
+
+  LOGFONT font_info;

[msw, 2015/01/12 22:29:29]

nit: Add a comment like "Create a font with a height near that of the target
height."

[ananta, 2015/01/12 23:08:02]

Done.

+  GetObject(GetNativeFont(), sizeof(LOGFONT), &font_info);
+  font_info.lfHeight = height;
+  SetLogFontStyle(style, &font_info);
+
+  HFONT hfont = CreateFontIndirect(&font_info);
+  Font font(new PlatformFontWin(CreateHFontRef(hfont)));
 
   // CreateFontIndirect() doesn't return the largest size for the given height
   // when decreasing the height. Iterate to find it.
-  if (GetHeight() > height) {
+  if (font.GetHeight() > height) {
     const int min_font_size = GetMinimumFontSize();
-    Font font = DeriveFont(-1, style);
+    font = font.Derive(-1, style);
     int font_height = font.GetHeight();
     int font_size = font.GetFontSize();
     while (font_height > height && font_size != min_font_size) {
@@ -231,13 +237,13 @@ Font PlatformFontWin::DeriveFontWithHeight(int height, int style) {
     return font;
   }
 
-  LOGFONT font_info;
-  GetObject(GetNativeFont(), sizeof(LOGFONT), &font_info);
-  font_info.lfHeight = height;
-  SetLogFontStyle(style, &font_info);
-
-  HFONT hfont = CreateFontIndirect(&font_info);
-  return DeriveWithCorrectedSize(hfont);
+  while (font.GetHeight() <= height) {

[Alexei Svitkine (slow), 2015/01/12 23:00:43]

Have you checked whether this extra loop doesn't cause any performance
regressions? In the past, I recall that we have had cases where bad performance
in this function resulted in a degradation of text rendering performance in UI.
Can you check whether this change is performance neutral or not?

[ananta, 2015/01/12 23:08:02]

We start off with a native font created with the target height which ensures
that the loop here will not have too many iterations to cause performance
issues. In the unittest runs the loop runs once at the most which is similar to
current behavior.

+    Font derived_font = font.Derive(1, style);

[msw, 2015/01/12 22:29:29]

nit: The loop above breaks if the derived font isn't any smaller than the
current font. I'm not sure if that's still a problem there, or if something
similar might happen here. If you want to be really safe, you can add a similar
break, otherwise you might want to just add a dcheck here:
DCHECK_GT(derived_font.GetFontSize(), font.GetFontSize());

[ananta, 2015/01/12 23:08:02]

Done.

+    if (derived_font.GetHeight() > height)
+      break;
+    font = derived_font;
+  }
+  return font;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -423,37 +429,6 @@ PlatformFontWin::HFontRef* PlatformFontWin::CreateHFontRefFromGDI(
                       ave_char_width, style);
 }
 
-Font PlatformFontWin::DeriveWithCorrectedSize(HFONT base_font) {
-  base::win::ScopedGetDC screen_dc(NULL);
-  gfx::ScopedSetMapMode mode(screen_dc, MM_TEXT);
-
-  base::win::ScopedGDIObject<HFONT> best_font(base_font);
-  TEXTMETRIC best_font_metrics;
-  GetTextMetricsForFont(screen_dc, best_font, &best_font_metrics);
-
-  LOGFONT font_info;
-  GetObject(base_font, sizeof(LOGFONT), &font_info);
-
-  // Set |lfHeight| to negative value to indicate it's the size, not the height.
-  font_info.lfHeight =
-      -(best_font_metrics.tmHeight - best_font_metrics.tmInternalLeading);
-
-  do {
-    // Increment font size. Prefer font with greater size if its height isn't
-    // greater than height of base font.
-    font_info.lfHeight = AdjustFontSize(font_info.lfHeight, 1);
-    base::win::ScopedGDIObject<HFONT> font(CreateFontIndirect(&font_info));
-    TEXTMETRIC font_metrics;
-    GetTextMetricsForFont(screen_dc, font, &font_metrics);
-    if (font_metrics.tmHeight > best_font_metrics.tmHeight)
-      break;
-    best_font.Set(font.release());
-    best_font_metrics = font_metrics;
-  } while (true);
-
-  return Font(new PlatformFontWin(CreateHFontRef(best_font.release())));
-}
-
 // static
 PlatformFontWin::HFontRef* PlatformFontWin::CreateHFontRefFromSkia(
     HFONT gdi_font,
@@ -518,8 +493,7 @@ PlatformFontWin::HFontRef* PlatformFontWin::CreateHFontRefFromSkia(
   // The calculations below are similar to those in the CreateHFontRef
   // function. The height, baseline and cap height are rounded up to ensure
   // that they match up closely with GDI.
-  const int height = std::ceil(
-      skia_metrics.fDescent - skia_metrics.fAscent + skia_metrics.fLeading);
+  const int height = std::ceil(skia_metrics.fDescent - skia_metrics.fAscent);
   const int baseline = std::max<int>(1, std::ceil(-skia_metrics.fAscent));
   const int cap_height = std::ceil(paint.getTextSize() *
       static_cast<double>(dwrite_font_metrics.capHeight) /