Add abliity to set textblob cache budget to GrContext

include/gpu/GrContext.h

Index: include/gpu/GrContext.h
diff --git a/include/gpu/GrContext.h b/include/gpu/GrContext.h
index c4691e4652e6c811755a8ca23abb54ac4949075d..ff4a0963a3b4ded7eec09b8afad7ede6e9a3df95 100644
--- a/include/gpu/GrContext.h
+++ b/include/gpu/GrContext.h
@@ -353,6 +353,10 @@ public:
     void dumpGpuStats(SkString*) const;
     void printGpuStats() const;
 
+    /** Specify the TextBlob cache limit. If the current cache exceeds this limit it will purge.
+        this is for testing only */
+    void setTextBlobCacheLimit_ForTesting(size_t bytes);
+
 private:
     GrGpu*                          fGpu;
     const GrCaps*                   fCaps;