Fix CJK font linking size on Windows XP.

ui/gfx/platform_font_win.cc

Index: ui/gfx/platform_font_win.cc
===================================================================
--- ui/gfx/platform_font_win.cc	(revision 134531)
+++ ui/gfx/platform_font_win.cc	(working copy)
@@ -47,6 +47,13 @@
   }
 }
 
+// Sets style properties on |font_info| based on |font_style|.
+void SetLogFontStyle(int font_style, LOGFONT* font_info) {
+  font_info->lfUnderline = (font_style & gfx::Font::UNDERLINED) != 0;
+  font_info->lfItalic = (font_style & gfx::Font::ITALIC) != 0;
+  font_info->lfWeight = (font_style & gfx::Font::BOLD) ? FW_BOLD : FW_NORMAL;
+}
+
 }  // namespace
 
 namespace gfx {
@@ -75,17 +82,39 @@
   InitWithFontNameAndSize(font_name, font_size);
 }
 
+Font PlatformFontWin::DeriveFontWithHeight(int height, int style) {
+  DCHECK_GE(height, 0);
+  if (GetHeight() == height && GetStyle() == style)
+    return Font(this);
+
+  // CreateFontIndirect() doesn't return the largest size for the given height
+  // when decreasing the height. Iterate to find it.
+  if (GetHeight() > height) {

[msw, 2012/04/30 17:40:01]

Should this heed the min locale height/size like AdjustFontSize?

[Alexei Svitkine (slow), 2012/04/30 17:49:14]

No, since DeriveFont() goes through AdjustFontSize().

[msw, 2012/04/30 18:55:39]

So an arg |height| < min will cause an infinite while loop since
|font.GetHeight()| will always exceed |height|? Please guard against this and
add a test case.

[Alexei Svitkine (slow), 2012/04/30 19:24:00]

Good catch. Fixed and added test.

+    Font font = this->DeriveFont(-1, style);

[msw, 2012/04/30 17:40:01]

Is there a name conflict or can you nix "this->"?

[Alexei Svitkine (slow), 2012/04/30 17:49:14]

Done.

+    while (font.GetHeight() > height) {
+      font = font.DeriveFont(-1, 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 Font(new PlatformFontWin(CreateHFontRef(hfont)));
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // PlatformFontWin, PlatformFont implementation:
 
 Font PlatformFontWin::DeriveFont(int size_delta, int style) const {
   LOGFONT font_info;
   GetObject(GetNativeFont(), sizeof(LOGFONT), &font_info);
-  font_info.lfHeight = AdjustFontSize(font_info.lfHeight, size_delta);
-  font_info.lfUnderline =
-      ((style & gfx::Font::UNDERLINED) == gfx::Font::UNDERLINED);
-  font_info.lfItalic = ((style & gfx::Font::ITALIC) == gfx::Font::ITALIC);
-  font_info.lfWeight = (style & gfx::Font::BOLD) ? FW_BOLD : FW_NORMAL;
+  const int requested_font_size = font_ref_->requested_font_size();
+  font_info.lfHeight = AdjustFontSize(-requested_font_size, size_delta);
+  SetLogFontStyle(style, &font_info);
 
   HFONT hfont = CreateFontIndirect(&font_info);
   return Font(new PlatformFontWin(CreateHFontRef(hfont)));
@@ -191,10 +220,11 @@
     GetTextMetrics(screen_dc, &font_metrics);
   }
 
-  const int height = std::max(1, static_cast<int>(font_metrics.tmHeight));
-  const int baseline = std::max(1, static_cast<int>(font_metrics.tmAscent));
-  const int ave_char_width =
-      std::max(1, static_cast<int>(font_metrics.tmAveCharWidth));
+  const int height = std::max<int>(1, font_metrics.tmHeight);
+  const int baseline = std::max<int>(1, font_metrics.tmAscent);
+  const int ave_char_width = std::max<int>(1, font_metrics.tmAveCharWidth);
+  const int font_size =
+      std::max<int>(1, font_metrics.tmHeight - font_metrics.tmInternalLeading);
   int style = 0;
   if (font_metrics.tmItalic)
     style |= Font::ITALIC;
@@ -203,7 +233,7 @@
   if (font_metrics.tmWeight >= kTextMetricWeightBold)
     style |= Font::BOLD;
 
-  return new HFontRef(font, height, baseline, ave_char_width, style);
+  return new HFontRef(font, font_size, height, baseline, ave_char_width, style);
 }
 
 PlatformFontWin::PlatformFontWin(HFontRef* hfont_ref) : font_ref_(hfont_ref) {
@@ -213,23 +243,26 @@
 // PlatformFontWin::HFontRef:
 
 PlatformFontWin::HFontRef::HFontRef(HFONT hfont,
+         int font_size,
          int height,
          int baseline,
          int ave_char_width,
          int style)
     : hfont_(hfont),
+      font_size_(font_size),
       height_(height),
       baseline_(baseline),
       ave_char_width_(ave_char_width),
       style_(style),
-      dlu_base_x_(-1) {
+      dlu_base_x_(-1),
+      requested_font_size_(font_size) {
   DLOG_ASSERT(hfont);
 
   LOGFONT font_info;
   GetObject(hfont_, sizeof(LOGFONT), &font_info);
   font_name_ = UTF16ToUTF8(string16(font_info.lfFaceName));
-  DCHECK_LT(font_info.lfHeight, 0);
-  font_size_ = -font_info.lfHeight;
+  if (font_info.lfHeight < 0)
+    requested_font_size_ = -font_info.lfHeight;
 }
 
 int PlatformFontWin::HFontRef::GetDluBaseX() {