retool image cache to be generic cache

src/core/SkBitmapProcState.cpp

Index: src/core/SkBitmapProcState.cpp
diff --git a/src/core/SkBitmapProcState.cpp b/src/core/SkBitmapProcState.cpp
index 0cf4d6c4ea3a58f5da1f79b2ea54b7cbca360613..d038e244ddf0076a4192a073ca238b615923bade 100644
--- a/src/core/SkBitmapProcState.cpp
+++ b/src/core/SkBitmapProcState.cpp
@@ -109,7 +109,7 @@ static SkScalar effective_matrix_scale_sqrd(const SkMatrix& mat) {
 
 class AutoScaledCacheUnlocker {
 public:
-    AutoScaledCacheUnlocker(SkScaledImageCache::ID** idPtr) : fIDPtr(idPtr) {}
+    AutoScaledCacheUnlocker(SkScaledImageCache::ID* idPtr) : fIDPtr(idPtr) {}
     ~AutoScaledCacheUnlocker() {
         if (fIDPtr && *fIDPtr) {
             SkScaledImageCache::Unlock(*fIDPtr);
@@ -123,7 +123,7 @@ public:
     }
 
 private:
-    SkScaledImageCache::ID** fIDPtr;
+    SkScaledImageCache::ID* fIDPtr;
 };
 #define AutoScaledCacheUnlocker(...) SK_REQUIRE_LOCAL_VAR(AutoScaledCacheUnlocker)