Rename GrContentKey to GrUniqueKey

Review URL: https://codereview.chromium.org/940463006
diff --git a/src/gpu/GrStencilAndCoverTextContext.cpp b/src/gpu/GrStencilAndCoverTextContext.cpp
index 3061ec6..9c3ba6a 100644
--- a/src/gpu/GrStencilAndCoverTextContext.cpp
+++ b/src/gpu/GrStencilAndCoverTextContext.cpp
@@ -207,9 +207,9 @@
                                   const SkTypeface* typeface,
                                   const SkDescriptor* desc,
                                   const SkStrokeRec& stroke) {
-    static const GrContentKey::Domain kDomain = GrContentKey::GenerateDomain();
-    GrContentKey key;
-    GrContentKey::Builder builder(&key, kDomain, 4);
+    static const GrUniqueKey::Domain kDomain = GrUniqueKey::GenerateDomain();
+    GrUniqueKey key;
+    GrUniqueKey::Builder builder(&key, kDomain, 4);
     struct GlyphKey {
         uint32_t fChecksum;
         uint32_t fTypeface;