cc: handle failed image transfer cache entry failure

This is the GpuImageDecodeCache equivalent of this change:
https://chromium-review.googlesource.com/c/chromium/src/+/1147102

Bug: 866434
Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;master.tryserver.blink:linux_trusty_blink_rel
Change-Id: I59da18646c0817f011a464b7571a9b6abf7b8455
Reviewed-on: https://chromium-review.googlesource.com/1147243Reviewed-by: Eric Karl <ericrk@chromium.org>
Commit-Queue: enne <enne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#577279}

cc/tiles/gpu_image_decode_cache.cc

@@ -1526,14 +1526,20 @@ void GpuImageDecodeCache::UploadImageIfNecessary(const DrawImage& draw_image,
                                               image_data->needs_mips);
     size_t size = image_entry.SerializedSize();
     void* data = context_->ContextSupport()->MapTransferCacheEntry(size);
-    // TODO(piman): handle error (failed to allocate/map shm)
-    DCHECK(data);
-    bool succeeded = image_entry.Serialize(
-        base::make_span(reinterpret_cast<uint8_t*>(data), size));
-    DCHECK(succeeded);
-    context_->ContextSupport()->UnmapAndCreateTransferCacheEntry(
-        image_entry.UnsafeType(), image_entry.Id());
-    image_data->upload.SetTransferCacheId(image_entry.Id());
+    if (data) {
+      bool succeeded = image_entry.Serialize(
+          base::make_span(reinterpret_cast<uint8_t*>(data), size));
+      DCHECK(succeeded);
+      context_->ContextSupport()->UnmapAndCreateTransferCacheEntry(
+          image_entry.UnsafeType(), image_entry.Id());
+      image_data->upload.SetTransferCacheId(image_entry.Id());
+    } else {
+      // Transfer cache entry can fail due to a lost gpu context or failure
+      // to allocate shared memory.  Handle this gracefully.  Mark this
+      // image as "decode failed" so that we do not try to handle it again.
+      // If this was a lost context, we'll recreate this image decode cache.
+      image_data->decode.decode_failure = true;
+    }
 
     return;
   }