Expose WebPMalloc() in addition to WebPFree()

and use it at various places, including for WebPData.

This is an API change!

Change-Id: Ic041323a1179c465292a4f981a86c4c34635d243

src/webp/types.h

@@ -7,7 +7,7 @@
 // be found in the AUTHORS file in the root of the source tree.
 // -----------------------------------------------------------------------------
 //
-//  Common types
+//  Common types + memory wrappers
 //
 // Author: Skal (pascal.massimino@gmail.com)
 
@@ -49,4 +49,20 @@ typedef long long int int64_t;
 // Macro to check ABI compatibility (same major revision number)
 #define WEBP_ABI_IS_INCOMPATIBLE(a, b) (((a) >> 8) != ((b) >> 8))
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// Allocates 'size' bytes of memory. Returns NULL upon error. Memory
+// must be deallocated by calling WebPFree(). This function is made available
+// by the core 'libwebp' library.
+WEBP_EXTERN void* WebPMalloc(size_t size);
+
+// Releases memory returned by the WebPDecode*() functions (from decode.h).
+WEBP_EXTERN void WebPFree(void* ptr);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
 #endif  // WEBP_WEBP_TYPES_H_