add realloc method to SkAutoSTMalloc

include/core/SkTemplates.h

Index: include/core/SkTemplates.h
diff --git a/include/core/SkTemplates.h b/include/core/SkTemplates.h
index b18556b4524b8bb713b25747ff51929a97a8998e..a6cfa52026d58f9cea2b163c4a0de7f1cec3cb7d 100644
--- a/include/core/SkTemplates.h
+++ b/include/core/SkTemplates.h
@@ -464,6 +464,23 @@ public:
         return fPtr[index];
     }
 
+    // Reallocs the array, can be used to shrink the allocation.  By reset above, we know fPtr's
+    // size is > N so the below memcpys are safe
+    void realloc(size_t count) {
+        if (count > N) {
+            if (fPtr == fTStorage) {
+                fPtr = (T*)sk_malloc_flags(count * sizeof(T), SK_MALLOC_THROW | SK_MALLOC_TEMP);

[mtklein, 2015/04/07 19:27:33]

Let's use sk_malloc_throw.  I don't believe SK_MALLOC_TEMP does anything, but if
it did this sure wouldn't be the place to use it.

+                memcpy(fPtr, fTStorage, N);
+            } else {
+                fPtr = (T*)sk_realloc_throw(fPtr, count * sizeof(T));
+            }
+        } else if (fPtr != fTStorage) {
+            memcpy(fTStorage, fPtr, N);

[mtklein, 2015/04/07 19:27:34]

Do you ever really hit this case that you shrink back into the static storage? 
If not, let's not bother?

+            SkDELETE(fPtr);
+            fPtr = fTStorage;
+        }
+    }
+
 private:
     T*          fPtr;
     union {