Harden a security CHECK in Font::individualCharacterRanges

third_party/WebKit/Source/platform/fonts/Font.cpp

Index: third_party/WebKit/Source/platform/fonts/Font.cpp
diff --git a/third_party/WebKit/Source/platform/fonts/Font.cpp b/third_party/WebKit/Source/platform/fonts/Font.cpp
index 8e0ec9b8e3c235324b44434cc36274cc3eb6483f..08cdaf32d686be7b736d9d96023e6a6d498dd40c 100644
--- a/third_party/WebKit/Source/platform/fonts/Font.cpp
+++ b/third_party/WebKit/Source/platform/fonts/Font.cpp
@@ -768,7 +768,11 @@ Vector<CharacterRange> Font::individualCharacterRanges(const TextRun& run) const
     FontCachePurgePreventer purgePreventer;
     CachingWordShaper shaper(m_fontFallbackList->shapeCache(m_fontDescription));
     auto ranges = shaper.individualCharacterRanges(this, run);
-    DCHECK_EQ(ranges.size(), static_cast<unsigned>(run.length()));
+    // The shaper should return ranges.size == run.length but on some platforms
+    // (OSX10.9.5) we are seeing cases in the upper end of the unicode range
+    // where this is not true (see: crbug.com/620952). To catch these cases on
+    // more popular platforms, and to protect users, we are using a CHECK here.
+    CHECK_EQ(ranges.size(), static_cast<unsigned>(run.length()));
     return ranges;
 }