Remove 'String::append' from some of the blink source.

Source/platform/network/HTTPParsers.cpp

Index: Source/platform/network/HTTPParsers.cpp
diff --git a/Source/platform/network/HTTPParsers.cpp b/Source/platform/network/HTTPParsers.cpp
old mode 100644
new mode 100755
index e557188493514fe12aec80518c21f6f428266bd0..422fb7a8ff82f0d8c7cb1a3e45116f3f03715f71
--- a/Source/platform/network/HTTPParsers.cpp
+++ b/Source/platform/network/HTTPParsers.cpp
@@ -129,10 +129,11 @@ bool isValidHTTPToken(const String& characters)
 static const size_t maxInputSampleSize = 128;
 static String trimInputSample(const char* p, size_t length)
 {
-    String s = String(p, std::min<size_t>(length, maxInputSampleSize));
-    if (length > maxInputSampleSize)
-        s.append(horizontalEllipsis);
-    return s;
+    if (length > maxInputSampleSize) {
+        String s = String(p, std::min<size_t>(length, maxInputSampleSize)) + horizontalEllipsis;
+        return s;
+    }
+    return String(p, std::min<size_t>(length, maxInputSampleSize));
 }
 
 ContentDispositionType contentDispositionType(const String& contentDisposition)