Switch WTF::find on LChar to use memchr.

third_party/WebKit/Source/wtf/text/StringImpl.h

Index: third_party/WebKit/Source/wtf/text/StringImpl.h
diff --git a/third_party/WebKit/Source/wtf/text/StringImpl.h b/third_party/WebKit/Source/wtf/text/StringImpl.h
index 161fa19be061c9ad496f7190c45a2f565eda7fc0..850c54ab74e45d896dffa4e3b8c38464a6ebee9e 100644
--- a/third_party/WebKit/Source/wtf/text/StringImpl.h
+++ b/third_party/WebKit/Source/wtf/text/StringImpl.h
@@ -31,6 +31,7 @@
 #include "wtf/WTFExport.h"
 #include "wtf/text/Unicode.h"
 #include <limits.h>
+#include <string.h>
 
 #if OS(MACOSX)
 typedef const struct __CFString * CFStringRef;
@@ -518,8 +519,14 @@ WTF_EXPORT bool equalIgnoringASCIICase(const StringImpl*, const LChar*);
 
 WTF_EXPORT int codePointCompareIgnoringASCIICase(const StringImpl*, const LChar*);
 
-template<typename CharacterType>
-inline size_t find(const CharacterType* characters, unsigned length, CharacterType matchCharacter, unsigned index = 0)
+inline size_t find(const LChar* characters, unsigned length, LChar matchCharacter, unsigned index = 0)
+{
+    const LChar* found = static_cast<const LChar*>(
+        memchr(characters + index, matchCharacter, length - index));

[Nico, 2016/05/10 17:47:06]

what if index > length?

[jbroman, 2016/05/11 17:19:32]

I'd expect that to be an error at the call site (it seems equivalent to indexing
past the end of the array). But I can check it, if you'd like.

+    return found ? found - characters : kNotFound;
+}
+
+inline size_t find(const UChar* characters, unsigned length, UChar matchCharacter, unsigned index = 0)
 {
     while (index < length) {
         if (characters[index] == matchCharacter)
@@ -541,6 +548,12 @@ inline size_t find(const LChar* characters, unsigned length, UChar matchCharacte
     return find(characters, length, static_cast<LChar>(matchCharacter), index);
 }
 
+template <typename CharacterType>
+inline size_t find(const CharacterType* characters, unsigned length, char matchCharacter, unsigned index = 0)
+{
+    return find(characters, length, static_cast<LChar>(matchCharacter), index);

[Nico, 2016/05/10 17:47:06]

why cast matchCharacter to LChar?

[jbroman, 2016/05/11 17:19:32]

To call the actual implementation above. Without the cast, this function calls
itself.

+}
+
 inline size_t find(const LChar* characters, unsigned length, CharacterMatchFunctionPtr matchFunction, unsigned index = 0)
 {
     while (index < length) {