Workaround for Issue 15949: cannot use the "WenQuanYi Bitmap Song" (chinese Fonts) as the system fonts with chrome

- Adding a font fallback code to Font::CreateFont() in font_skia.cc so that Chromium can startup even when a non-scalable font is selected as an application font. If the application font is non-scalable, Font::CreateFont() loads a _scalable_ "sans" font as a fallback.
  (Note: The function still never load non-scalable fonts.)
- Removed a comment for issue 12530 since the issue has been fixed.

BUG=12530
BUG=15949
TEST=Download the snap.pcf font from http://artwizaleczapka.sourceforge.net/ and put it to ~/.fonts/. Remove temporarily /etc/fonts/conf.d/70-no-bitmaps.conf and run "fc-cache -f". Start /ust/bin/gnome-appearance-properties and select "snap" as your application font. Then start chromium and verify that it does not crash (by the CHECK failure) on startup.

Review URL: http://codereview.chromium.org/207009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@26652 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 23 insertions, 4 deletions

diff --git a/app/gfx/font_skia.cc b/app/gfx/font_skia.cc
index 1779635..56851e0 100644
--- a/app/gfx/font_skia.cc
+++ b/app/gfx/font_skia.cc
@@ -6,10 +6,20 @@
 
 #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 {
+
+// The font family name which is used when a user's application font for
+// GNOME/KDE is a non-scalable one. The name should be listed in the
+// IsFallbackFontAllowed function in skia/ext/SkFontHost_fontconfig_direct.cpp.
+const char* kFallbackFontFamilyName = "sans";
+
+}  // namespace
+
 namespace gfx {
 
 Font::Font(const Font& other) {
@@ -89,15 +99,24 @@ int Font::ave_char_width() const {
 
 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);
-  // Temporary CHECK for tracking down
-  // http://code.google.com/p/chromium/issues/detail?id=12530
-  CHECK(tf) << "Could not find font: " << base::SysWideToUTF8(font_family);
+  if (!tf) {
+    // A non-scalable font such as .pcf is specified. Falls back to a default
+    // scalable font.
+    tf = SkTypeface::CreateFromName(
+        kFallbackFontFamilyName, SkTypeface::kNormal);
+    CHECK(tf) << "Could not find any font: "
+              << base::SysWideToUTF8(font_family)
+              << ", " << kFallbackFontFamilyName;
+    fallback = base::SysUTF8ToWide(kFallbackFontFamilyName);
+  }
   SkAutoUnref tf_helper(tf);
 
-  return Font(tf, font_family, font_size, NORMAL);
+  return Font(
+      tf, fallback.empty() ? font_family : fallback, font_size, NORMAL);
 }
 
 Font Font::DeriveFont(int size_delta, int style) const {