Cleanup of GrFontDescKey

src/core/SkDescriptor.h

Index: src/core/SkDescriptor.h
diff --git a/src/core/SkDescriptor.h b/src/core/SkDescriptor.h
index 0693ccfe60d82226b95eb5f73e69fc16b46cd9de..e559215cb169dc0c502fe1358783a07d202dcac5 100644
--- a/src/core/SkDescriptor.h
+++ b/src/core/SkDescriptor.h
@@ -136,6 +136,11 @@ class SkAutoDescriptor : SkNoncopyable {
 public:
     SkAutoDescriptor() : fDesc(NULL) {}
     SkAutoDescriptor(size_t size) : fDesc(NULL) { this->reset(size); }
+    SkAutoDescriptor(const SkDescriptor& desc) : fDesc(NULL) {
+        size_t size = desc.getLength();
+        this->reset(size);
+        memcpy(fDesc, &desc, size);
+    }
 
     ~SkAutoDescriptor() { this->free(); }