Eliminate one copy of replace_char() function.

src/core/SkString.cpp

Index: src/core/SkString.cpp
diff --git a/src/core/SkString.cpp b/src/core/SkString.cpp
index 48459dbbd8ac69eabb6f2f72cbbf1c9ff862e7f5..db85d188a5432e4bbb15867077877ff3fc0b8174 100644
--- a/src/core/SkString.cpp
+++ b/src/core/SkString.cpp
@@ -620,6 +620,14 @@ void SkString::remove(size_t offset, size_t length) {
     }
 }
 
+void SkString::replace(SkUnichar oldChar, SkUnichar newChar) {
+    for (size_t i = 0; i < size(); ++i) {
+        if (oldChar == this->operator[](i)) {
+            this->operator[](i) = newChar;
+        }
+    }
+}
+
 void SkString::swap(SkString& other) {
     this->validate();
     other.validate();