add textblob cache freeall

src/gpu/GrTextBlobCache.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrTextBlobCache_DEFINED
 #define GrTextBlobCache_DEFINED
 
@@ skipping 97 matching lines @@
 
     void makeMRU(BitmapTextBlob* blob) {
         if (fBlobList.head() == blob) {
             return;
         }
 
         fBlobList.remove(blob);
         fBlobList.addToHead(blob);
     }
 
+    void freeAll();
+
 private:
     // TODO move to SkTextBlob
     void BlobGlyphCount(int* glyphCount, int* runCount, const SkTextBlob* blob) {
         SkTextBlob::RunIterator itCounter(blob);
         for (; !itCounter.done(); itCounter.next(), (*runCount)++) {
             *glyphCount += itCounter.glyphCount();
         }
     }
 
     typedef SkTInternalLList<BitmapTextBlob> BitmapBlobList;
 
     // Budget was chosen to be ~4 megabytes.  The min alloc and pre alloc sizes in the pool are
     // based off of the largest cached textblob I have seen in the skps(a couple of kilobytes).
     static const int kPreAllocSize = 1 << 17;
     static const int kMinGrowthSize = 1 << 17;
     static const int kBudget = 1 << 22;
     BitmapBlobList fBlobList;
     SkTDynamicHash<BitmapTextBlob, BitmapTextBlob::Key> fCache;
     GrMemoryPool fPool;
     PFOverBudgetCB fCallback;
     void* fData;
 };
 
 #endif