Add request cache to SkFontHost_fontconfig.

src/core/SkResourceCache.h

Index: src/core/SkResourceCache.h
diff --git a/src/core/SkResourceCache.h b/src/core/SkResourceCache.h
index a748133c964d74a2b8e3422c6e3c5563da9ddd3b..9e260a4d988d980d16bf3d2ea580bb4ad4d9ea2a 100644
--- a/src/core/SkResourceCache.h
+++ b/src/core/SkResourceCache.h
@@ -29,15 +29,17 @@ class SkTraceMemoryDump;
 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; }