Move the GlyphCache to use a hash table instead of doing its own ad-hoc

src/core/SkGlyph.h

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkGlyph_DEFINED
 #define SkGlyph_DEFINED
 
+#include "SkChecksum.h"
 #include "SkTypes.h"
 #include "SkFixed.h"
 #include "SkMask.h"
 
 class SkPath;
 class SkGlyphCache;
 
 // needs to be != to any valid SkMask::Format
 #define MASK_FORMAT_UNKNOWN         (0xFF)
 #define MASK_FORMAT_JUST_ADVANCE    MASK_FORMAT_UNKNOWN
@@ skipping 86 matching lines @@
     size_t computeImageSize() const;
 
     /** Call this to set all of the metrics fields to 0 (e.g. if the scaler
         encounters an error measuring a glyph). Note: this does not alter the
         fImage, fPath, fID, fMaskFormat fields.
      */
     void zeroMetrics();
 
     void toMask(SkMask* mask) const;
 
+    class HashTraits {
+    public:
+        static uint32_t GetKey(const SkGlyph& glyph) {
+            return glyph.fID;
+        }
+        static uint32_t Hash(uint32_t glyphId) {
+            return SkChecksum::CheapMix(glyphId);
+        }
+    };
+
  private:
     // TODO(herb) remove friend statement after SkGlyphCache cleanup.
     friend class SkGlyphCache;
 
     void initCommon(uint32_t id) {
         fID             = id;
         fImage          = NULL;
         fPath           = NULL;
         fMaskFormat     = MASK_FORMAT_UNKNOWN;
         fForceBW        = 0;
@@ skipping 39 matching lines @@
 
   // FIXME - This is needed because the Android frame work directly
   // accesses fID. Remove when fID accesses are cleaned up.
 #ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
   public:
 #endif
     uint32_t    fID;
 };
 
 #endif