First pass at font cache refactor: Create an atlas manager per texture

src/gpu/GrAtlas.h

Index: src/gpu/GrAtlas.h
diff --git a/src/gpu/GrAtlas.h b/src/gpu/GrAtlas.h
index e4472e7c13fbe7bc2b5b350f0a29a1159f1334a0..3f9da8cb13703eeea01b5aaa7de95ba9b40f84a9 100644
--- a/src/gpu/GrAtlas.h
+++ b/src/gpu/GrAtlas.h
@@ -64,25 +64,24 @@ class GrPlotMgr;
 
 class GrAtlasMgr {
 public:
-    GrAtlasMgr(GrGpu*);
+    GrAtlasMgr(GrGpu*, GrMaskFormat);
     ~GrAtlasMgr();
 
-    GrAtlas* addToAtlas(GrAtlas**, int width, int height, const void*,
-                        GrMaskFormat, GrIPoint16*);
+    GrAtlas* addToAtlas(GrAtlas**, int width, int height, const void*, GrIPoint16*);
     void deleteAtlas(GrAtlas* atlas) { delete atlas; }
 
-    GrTexture* getTexture(GrMaskFormat format) const {
-        SkASSERT((unsigned)format < kCount_GrMaskFormats);
-        return fTexture[format];
+    GrTexture* getTexture() const {
+        return fTexture;
     }
 
     // to be called by ~GrAtlas()
-    void freePlot(GrMaskFormat format, int x, int y);
+    void freePlot(int x, int y);
 
 private:
-    GrGpu*      fGpu;
-    GrTexture*  fTexture[kCount_GrMaskFormats];
-    GrPlotMgr*  fPlotMgr[kCount_GrMaskFormats];
+    GrGpu*       fGpu;
+    GrMaskFormat fMaskFormat;
+    GrTexture*   fTexture;
+    GrPlotMgr*   fPlotMgr;
 };
 
 #endif