Support different formats in the same resource pool.

cc/resources/resource_format.cc

Index: cc/resources/resource_format.cc
diff --git a/cc/resources/resource_format.cc b/cc/resources/resource_format.cc
index 45581b800f140f3b6725a6bae4959686e66f03d0..7348f0335b004f333c2d4ac5621e55356561da15 100644
--- a/cc/resources/resource_format.cc
+++ b/cc/resources/resource_format.cc
@@ -25,4 +25,13 @@ SkColorType ResourceFormatToSkColorType(ResourceFormat format) {
   return kN32_SkColorType;
 }
 
+bool IsFormatCompressed(ResourceFormat format) {
+  switch (format) {
+    case ETC1:
+      return true;
+    default:
+      return false;
+  }
+}
+
 }  // namespace cc