rename ScaledImageCache to ResourceCache

BUG=skia:
R=bsalomon@google.com, mtklein@google.com

Author: reed@google.com

Review URL: https://codereview.chromium.org/511283002
diff --git a/gyp/core.gypi b/gyp/core.gypi
index dc72853..308cc6e 100644
--- a/gyp/core.gypi
+++ b/gyp/core.gypi
@@ -167,10 +167,10 @@
         '<(skia_src_path)/core/SkRegion.cpp',
         '<(skia_src_path)/core/SkRegionPriv.h',
         '<(skia_src_path)/core/SkRegion_path.cpp',
+        '<(skia_src_path)/core/SkResourceCache.cpp',
         '<(skia_src_path)/core/SkRRect.cpp',
         '<(skia_src_path)/core/SkRTree.h',
         '<(skia_src_path)/core/SkRTree.cpp',
-        '<(skia_src_path)/core/SkScaledImageCache.cpp',
         '<(skia_src_path)/core/SkScalar.cpp',
         '<(skia_src_path)/core/SkScalerContext.cpp',
         '<(skia_src_path)/core/SkScalerContext.h',