add replace_char() method to SkString API (skbug.com/2651)

tests/StringTest.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include <stdarg.h>
 #include <stdio.h>
 #include "SkString.h"
@@ skipping 168 matching lines @@
     REPORTER_ASSERT(reporter, buffer[18] == 'a');
     REPORTER_ASSERT(reporter, buffer[19] == 'a');
     REPORTER_ASSERT(reporter, buffer[20] == 'a');
     printfAnalog(buffer, 20, "%30d", 0);
     REPORTER_ASSERT(reporter, buffer[18] == ' ');
     REPORTER_ASSERT(reporter, buffer[19] == 0);
     REPORTER_ASSERT(reporter, buffer[20] == 'a');
 
 }
 
+DEF_TEST(String_ReplaceChar, r) {
+    a.set("hello world");
+    a.replaceChar('h', 'h');
+    REPORTER_ASSERT(reporter, a.equals("hello world"));
+    a.replaceChar('x', 'x');
+    REPORTER_ASSERT(reporter, a.equals("hello world"));
+    a.replaceChar('o', 'e');
+    REPORTER_ASSERT(reporter, a.equals("helle werld"));
+    a.replaceChar('x', 'e');
+    REPORTER_ASSERT(reporter, a.equals("helle werld"));
+    a.replaceChar('x', 'z');
+    REPORTER_ASSERT(reporter, a.equals("helle werld"));
+    a.set("");
+    a.replaceChar('a', 'b');
+    REPORTER_ASSERT(reporter, a.equals(""));
+}
+
 DEF_TEST(String_SkStrSplit, r) {
     SkTArray<SkString> results;
 
     SkStrSplit("a-_b_c-dee--f-_-_-g-", "-_", &results);
     REPORTER_ASSERT(r, results.count() == 6);
     REPORTER_ASSERT(r, results[0].equals("a"));
     REPORTER_ASSERT(r, results[1].equals("b"));
     REPORTER_ASSERT(r, results[2].equals("c"));
     REPORTER_ASSERT(r, results[3].equals("dee"));
     REPORTER_ASSERT(r, results[4].equals("f"));
     REPORTER_ASSERT(r, results[5].equals("g"));
 }