Attempt to fallback to some matching font in the GetMatchingDirectWriteFontForTypeface function in …

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 df2b874b64b6fbf2b2062142d9ccaa6cac299092..68c7284f55c6d9e3c3877a9dd650920c6dbc68bf 100644
--- a/ui/gfx/platform_font_win.cc
+++ b/ui/gfx/platform_font_win.cc
@@ -9,6 +9,7 @@
 #include <math.h>
 #include <windows.h>
 
+#include "base/debug/alias.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/strings/string_util.h"
@@ -125,10 +126,44 @@ HRESULT GetMatchingDirectWriteFontForTypeface(const wchar_t* face_name,
   DWRITE_FONT_STYLE italic = (font_style & SkTypeface::kItalic)
                             ? DWRITE_FONT_STYLE_ITALIC
                             : DWRITE_FONT_STYLE_NORMAL;
+
+  // The IDWriteFontFamily::GetFirstMatchingFont call fails on certain machines
+  // for fonts like MS UI Gothic, Segoe UI, etc. It is not clear why these
+  // fonts could be accessible to GDI and not to DirectWrite.
+  // The code below adds some debug fields to help track down these failures.
+  // 1. We get the matching font list for the font attributes passed in.
+  // 2. We get the font count in the family with a debug alias variable.
+  // 3. If we fail to get the font via the GetFirstMatchingFont call then we
+  //    try to get the first matching font in the IDWriteFontList.
+  // 4. If GetFirstMatchingFont and IDWriteFontList both fail then we CHECK as
+  //    before.
+  // Next step would be to remove the CHECKs in this function and fallback to
+  // GDI.
+  // http://crbug.com/434425

[Shrikant Kelkar, 2014/11/19 23:30:47]

If you want to look for specific fonts that are causing this.. add something
similar to dwrite_font_platform_win.cc

    base::debug::SetCrashKeyValue(kFontKeyName,
                                  base::WideToUTF8(font_key_name));

[ananta, 2014/11/19 23:38:58]

Will do that in a followup. Dunno what the clean up implications are here.

+  base::win::ScopedComPtr<IDWriteFontList> matching_font_list;
+  hr = font_family->GetMatchingFonts(weight, stretch, italic,
+                                     matching_font_list.Receive());
+  uint32 matching_font_count = 0;
+  if (SUCCEEDED(hr))
+    matching_font_count = matching_font_list->GetFontCount();
+
+  bool fallback_to_matching_font = false;
+
   hr = font_family->GetFirstMatchingFont(weight, stretch, italic,
                                          dwrite_font);
-  if (FAILED(hr))
+  if (FAILED(hr)) {
+    if (matching_font_list) {
+      hr = matching_font_list->GetFont(0, dwrite_font);
+      if (SUCCEEDED(hr))
+        fallback_to_matching_font = true;
+    }
+  }
+
+  if (FAILED(hr)) {
+    base::debug::Alias(&matching_font_count);
+    base::debug::Alias(&fallback_to_matching_font);

[Shrikant Kelkar, 2014/11/19 23:30:47]

fallback_to_matching_font = true if SUCCEEDED(hr) 
No use of Alias then here?

[ananta, 2014/11/19 23:38:58]

Moved the alias for fallback_to_matching_font above.

     CHECK(false);
+  }
   return hr;
 }