Add request cache to SkFontHost_fontconfig.

src/core/SkResourceCache.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkResourceCache_DEFINED
 #define SkResourceCache_DEFINED
 
@@ skipping 11 matching lines @@
  *  Multiple caches can be instantiated, but each instance is not implicitly
  *  thread-safe, so if a given instance is to be shared across threads, the
  *  caller must manage the access itself (e.g. via a mutex).
  *
  *  As a convenience, a global instance is also defined, which can be safely
  *  access across threads via the static methods (e.g. FindAndLock, etc.).
  */
 class SkResourceCache {
 public:
     struct Key {
-        // Call this to access your private contents. Must not use the address after calling init()
-        void* writableContents() { return this + 1; }
-
         // must call this after your private data has been written.
         // nameSpace must be unique per Key subclass.
         // sharedID == 0 means ignore this field : does not support group purging.
         // length must be a multiple of 4
         void init(void* nameSpace, uint64_t sharedID, size_t length);
 
+        /** Returns the size of this key. */
+        size_t length() {

[reed1, 2016/02/17 14:12:52]

size_t size() const { ...

[bungeman-skia, 2016/02/17 16:55:36]

Heh, yes,
http://stackoverflow.com/questions/300522/count-vs-length-vs-size-in-a-collec...
. I agree that this should be 'size', and I'm gonna change it, but the parameter
to 'init' that this is effectively mirroring is named 'length' (and it isn't
immediately clear which length it's referring to). I'll change that too then
just for sanity.

If only the STL had promoted a consistent naming convention.

+            return fCount32 << 2;
+        }
+
         void* getNamespace() const { return fNamespace; }
         uint64_t getSharedID() const { return ((uint64_t)fSharedID_hi << 32) | fSharedID_lo; }
 
         // This is only valid after having called init().
         uint32_t hash() const { return fHash; }
 
         bool operator==(const Key& other) const {
             const uint32_t* a = this->as32();
             const uint32_t* b = other.as32();
             for (int i = 0; i < fCount32; ++i) {  // (This checks fCount == other.fCount first.)
@@ skipping 226 matching lines @@
 
     void init();    // called by constructors
 
 #ifdef SK_DEBUG
     void validate() const;
 #else
     void validate() const {}
 #endif
 };
 #endif