use typedef to name our ID type in SkImageCache

include/lazy/SkPurgeableImageCache.h

Index: include/lazy/SkPurgeableImageCache.h
diff --git a/include/lazy/SkPurgeableImageCache.h b/include/lazy/SkPurgeableImageCache.h
index 0516ff18eff5a40c90d89a80f3156b9f368e29e4..cc2db819f9042d3f04b20dbf5aad05a63b8b990d 100644
--- a/include/lazy/SkPurgeableImageCache.h
+++ b/include/lazy/SkPurgeableImageCache.h
@@ -22,13 +22,13 @@ class SkPurgeableImageCache : public SkImageCache {
 public:
     static SkImageCache* Create();
 
-    virtual void* allocAndPinCache(size_t bytes, intptr_t* ID) SK_OVERRIDE;
-    virtual void* pinCache(intptr_t ID, SkImageCache::DataStatus*) SK_OVERRIDE;
-    virtual void releaseCache(intptr_t ID) SK_OVERRIDE;
-    virtual void throwAwayCache(intptr_t ID) SK_OVERRIDE;
+    virtual void* allocAndPinCache(size_t bytes, ID*) SK_OVERRIDE;
+    virtual void* pinCache(ID, SkImageCache::DataStatus*) SK_OVERRIDE;
+    virtual void releaseCache(ID) SK_OVERRIDE;
+    virtual void throwAwayCache(ID) SK_OVERRIDE;
 
 #ifdef SK_DEBUG
-    virtual MemoryStatus getMemoryStatus(intptr_t ID) const SK_OVERRIDE;
+    virtual MemoryStatus getMemoryStatus(ID) const SK_OVERRIDE;
     virtual void purgeAllUnpinnedCaches() SK_OVERRIDE;
     virtual ~SkPurgeableImageCache();
 #endif
@@ -37,9 +37,9 @@ private:
     SkPurgeableImageCache();
 
 #ifdef SK_DEBUG
-    SkTDArray<intptr_t> fRecs;
-    int findRec(intptr_t) const;
+    SkTDArray<ID> fRecs;
+    int findRec(ID) const;
 #endif
-    void removeRec(intptr_t);
+    void removeRec(ID);
 };
 #endif // SkPurgeableImageCache_DEFINED