GPU Font Cache improvements:

src/gpu/GrTextStrike.h

Index: src/gpu/GrTextStrike.h
diff --git a/src/gpu/GrTextStrike.h b/src/gpu/GrTextStrike.h
index 25ced6de9bd3044a44a1fa686db52aca80e6a556..bb48c2a20f0493b78dd8ccc95826754cec93ac19 100644
--- a/src/gpu/GrTextStrike.h
+++ b/src/gpu/GrTextStrike.h
@@ -46,6 +46,11 @@ public:
     }
     GrAtlas* getAtlas() const { return fAtlas; }
 
+    // returns true if an atlas was removed
+    bool removeUnusedAtlas();
+
+    void markAtlasesUnused();
+
 public:
     // for LRU
     GrTextStrike*   fPrev;
@@ -81,6 +86,9 @@ public:
 
     void purgeExceptFor(GrTextStrike*);
 
+    // remove an unused atlas and its strike (if necessary)
+    void freeAtlasExceptFor(GrTextStrike*);
+
     // testing
     int countStrikes() const { return fCache.getArray().count(); }
     const GrTextStrike* strikeAt(int index) const {