Change GrTextContext fallbacks to be a linked list chain.

src/gpu/GrTextContext.h

Index: src/gpu/GrTextContext.h
diff --git a/src/gpu/GrTextContext.h b/src/gpu/GrTextContext.h
index b82a64840b1f95d28a96bd20bfc0b0f4fbf6139a..95344dd39fbea0ee3e7c4095c828ae0c88bc1f63 100644
--- a/src/gpu/GrTextContext.h
+++ b/src/gpu/GrTextContext.h
@@ -23,18 +23,17 @@ class GrFontScaler;
  */
 class GrTextContext {
 public:
-    virtual ~GrTextContext() {}
+    virtual ~GrTextContext();
 
-    virtual bool canDraw(const SkPaint& paint) = 0;
-
-    virtual void drawText(const GrPaint&, const SkPaint&, const char text[], size_t byteLength,
-                          SkScalar x, SkScalar y) = 0;
-    virtual void drawPosText(const GrPaint&, const SkPaint&,
-                             const char text[], size_t byteLength,
-                             const SkScalar pos[], int scalarsPerPosition,
-                             const SkPoint& offset) = 0;
+    bool drawText(const GrPaint&, const SkPaint&, const char text[], size_t byteLength,
+                  SkScalar x, SkScalar y);
+    bool drawPosText(const GrPaint&, const SkPaint&,
+                     const char text[], size_t byteLength,
+                     const SkScalar pos[], int scalarsPerPosition,
+                     const SkPoint& offset);
 
 protected:
+    GrTextContext*     fFallbackTextContext;
     GrContext*         fContext;
     SkDeviceProperties fDeviceProperties;
 
@@ -45,6 +44,15 @@ protected:
 
     GrTextContext(GrContext*, const SkDeviceProperties&);
 
+    virtual bool canDraw(const SkPaint& paint) = 0;
+
+    virtual void onDrawText(const GrPaint&, const SkPaint&, const char text[], size_t byteLength,
+                            SkScalar x, SkScalar y) = 0;
+    virtual void onDrawPosText(const GrPaint&, const SkPaint&,
+                               const char text[], size_t byteLength,
+                               const SkScalar pos[], int scalarsPerPosition,
+                               const SkPoint& offset) = 0;
+
     void init(const GrPaint&, const SkPaint&);
     void finish() { fDrawTarget = NULL; }