oop: Fix transfer cache early out on bad image

This fixes a fuzzer null dereference.

Bug: 819562
Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.android:android_optional_gpu_tests_rel
Change-Id: Ia2e7138b6fd143ecd187679843f695c81e65bb63
Reviewed-on: https://chromium-review.googlesource.com/953143Reviewed-by: Eric Karl <ericrk@chromium.org>
Commit-Queue: enne <enne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#541541}

cc/paint/image_transfer_cache_entry.cc

@@ -131,7 +131,7 @@ bool ServiceImageTransferCacheEntry::Deserialize(
     if (!image)
       return false;
     image_ = image->makeTextureImage(context, nullptr);
-    if (!image)
+    if (!image_)
       return false;
     if (target_color_space) {
       image_ = image_->makeColorSpace(target_color_space,