skia: Add SK_API to SkDiscardableMemory.

src/core/SkDiscardableMemory.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkDiscardableMemory_DEFINED
 #define SkDiscardableMemory_DEFINED
 
 #include "SkTypes.h"
 
 /**
  *  Interface for discardable memory. Implementation is provided by the
  *  embedder.
  */
-class SkDiscardableMemory {
+class SK_API SkDiscardableMemory {
 
 public:
     /**
      *  Factory method that creates, initializes and locks an SkDiscardableMemory
      *  object. If either of these steps fails, a NULL pointer will be returned.
      */
     static SkDiscardableMemory* Create(size_t bytes);
 
     /** Must not be called while locked.
      */
@@ skipping 17 matching lines @@
     virtual void* data() = 0;
 
     /**
      * Unlock the memory so that it can be purged by the system. Must be called
      * after every successful lock call.
      */
     virtual void unlock() = 0;
 };
 
 #endif