Fix SkTableColorFilter deserialization validation.

Broken in https://skia.googlesource.com/skia/+/9fa60daad4d5f54c0dbe3dbcc7608a8f6d721187.

R=reed@google.com
TBR=reed@google.com

BUG=skia:

Author: senorblanco@chromium.org

Review URL: https://codereview.chromium.org/604873004
diff --git a/src/effects/SkTableColorFilter.cpp b/src/effects/SkTableColorFilter.cpp
index 88b4a4b..4853f73 100644
--- a/src/effects/SkTableColorFilter.cpp
+++ b/src/effects/SkTableColorFilter.cpp
@@ -198,7 +198,7 @@
     uint8_t unpackedStorage[4*256];
     size_t unpackedSize = SkPackBits::Unpack8(packedStorage, packedSize, unpackedStorage);
     // now check that we got the size we expected
-    if (!buffer.validate(unpackedSize != count*256)) {
+    if (!buffer.validate(unpackedSize == count*256)) {
         return NULL;
     }