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..54d4d5dbfbc0314f6c417ebc4615ff43c52e5ade 100644
--- a/include/core/SkTemplates.h
+++ b/include/core/SkTemplates.h
@@ -464,6 +464,17 @@ 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 memcpy is safe
+    void realloc(size_t count) {

[mtklein, 2015/04/07 19:59:44]

Don't we still need a count > N check for safety?

+        if (fPtr == fTStorage) {
+            fPtr = (T*)sk_malloc_throw(count * sizeof(T));
+            memcpy(fPtr, fTStorage, N);
+        } else {
+            fPtr = (T*)sk_realloc_throw(fPtr, count * sizeof(T));
+        }
+    }
+
 private:
     T*          fPtr;
     union {