Have codePointAt DCHECKS apply to 8bit strings too

third_party/WebKit/Source/platform/text/TextRun.h

Index: third_party/WebKit/Source/platform/text/TextRun.h
diff --git a/third_party/WebKit/Source/platform/text/TextRun.h b/third_party/WebKit/Source/platform/text/TextRun.h
index c6c78cec92189d2b274c4f00e0f30c7c87234ff5..2d4660a12286a5b5866c2e22aba68f3138ba6414 100644
--- a/third_party/WebKit/Source/platform/text/TextRun.h
+++ b/third_party/WebKit/Source/platform/text/TextRun.h
@@ -183,19 +183,19 @@ class PLATFORM_EXPORT TextRun final {
   }
 
   UChar32 codepointAt(unsigned i) const {
+    SECURITY_DCHECK(i < m_len);
     if (is8Bit())
       return (*this)[i];
     UChar32 codepoint;
-    SECURITY_DCHECK(i < m_len);
     U16_GET(characters16(), 0, i, m_len, codepoint);
     return codepoint;
   }
 
   UChar32 codepointAtAndNext(unsigned& i) const {
+    SECURITY_DCHECK(i < m_len);
     if (is8Bit())
       return (*this)[i++];
     UChar32 codepoint;
-    SECURITY_DCHECK(i < m_len);
     U16_NEXT(characters16(), i, m_len, codepoint);
     return codepoint;
   }