Remove wtf::String::characterAt.

third_party/WebKit/Source/core/editing/GranularityStrategyTest.cpp

Index: third_party/WebKit/Source/core/editing/GranularityStrategyTest.cpp
diff --git a/third_party/WebKit/Source/core/editing/GranularityStrategyTest.cpp b/third_party/WebKit/Source/core/editing/GranularityStrategyTest.cpp
index 36ac9fb7c0278a81a52c4c4843cb491c3b2fa3d5..dac7bae0998fd011a3260e3d1ab0a62c7425a988 100644
--- a/third_party/WebKit/Source/core/editing/GranularityStrategyTest.cpp
+++ b/third_party/WebKit/Source/core/editing/GranularityStrategyTest.cpp
@@ -126,7 +126,7 @@ void GranularityStrategyTest::parseText(const TextNodeVector& textNodes)
         String str = text->wholeText();
         for (size_t i = 0; i < str.length(); i++) {
             m_letterPos.append(visiblePositionToContentsPoint(createVisiblePosition(Position(text, i))));
-            char c = str.characterAt(i);
+            char c = str[i];
             if (isASCIIAlphanumeric(c) && !wordStarted) {
                 wordStartIndex = i + wordStartIndexOffset;
                 wordStarted = true;