Convert SkWriter32 to use an SkTDArray for its internal storage.

bench/WriterBench.cpp

Index: bench/WriterBench.cpp
diff --git a/bench/WriterBench.cpp b/bench/WriterBench.cpp
index 46b26b1efae3dd68992343f0d183d72762b499b7..7696eab8322eb5e42aa6dae4f069805f77daf316 100644
--- a/bench/WriterBench.cpp
+++ b/bench/WriterBench.cpp
@@ -24,7 +24,7 @@ protected:
     virtual void onDraw(const int loops, SkCanvas*) SK_OVERRIDE {
         static const char gStr[] = "abcdefghimjklmnopqrstuvwxyz";
         static const size_t gLen = strlen(gStr);
-        SkWriter32 writer(256 * 4);
+        SkWriter32 writer;
         for (int i = 0; i < loops; i++) {
             for (size_t j = 0; j <= gLen; j++) {
                 writer.writeString(gStr, j);