Implement EmbeddedWorkerContextClient.setCachedMetadata/clearCachedMetadata

content/common/service_worker/service_worker_messages.h

Index: content/common/service_worker/service_worker_messages.h
diff --git a/content/common/service_worker/service_worker_messages.h b/content/common/service_worker/service_worker_messages.h
index a9613b9385609683f7b8b2dd4314dcc3fbbb7279..e17812a9b8360c232ed69c04e1607fa7758b3a20 100644
--- a/content/common/service_worker/service_worker_messages.h
+++ b/content/common/service_worker/service_worker_messages.h
@@ -230,6 +230,16 @@ IPC_MESSAGE_ROUTED3(ServiceWorkerHostMsg_PostMessageToDocument,
                     base::string16 /* message */,
                     std::vector<int> /* sent_message_port_ids */)
 
+// Renderer -> Browser message to request that the browser cache |data|
+// associated with |url|.
+IPC_MESSAGE_ROUTED2(ServiceWorkerHostMsg_SetCachedMetadata,
+                    GURL /* url */,
+                    std::vector<char> /* data */)

[michaeln, 2015/02/18 03:37:34]

how large can the data be?

[horo, 2015/02/18 04:17:06]

Pickle::WriteBytes() treats the length as int.
So I think this can be 2GB.

[michaeln, 2015/02/18 19:17:00]

I guess I meant how large is this in practice. Processing very large messages
can be janky.

fyi, the ipc system puts a limit on the size of messages and the diskcache also
puts a limit on the size of resources.

ipc_channel.h
  // The maximum message size in bytes. Attempting to receive a message of this
  // size or bigger results in a channel error.
  static const size_t kMaximumMessageSize = 128 * 1024 * 1024;

[horo, 2015/02/19 00:08:43]

According to the UMA of V8.CodeCacheSizeRatio, the size of cached metadata seems
like less than 10x of the original code.
I think it is not very large.

+
+// Renderer -> Browser message to request that the browser clear the cache
+// associated with |url|.
+IPC_MESSAGE_ROUTED1(ServiceWorkerHostMsg_ClearCachedMetadata, GURL /* url */)
+
 // Ask the browser to open a tab/window (renderer->browser).
 IPC_MESSAGE_ROUTED2(ServiceWorkerHostMsg_OpenWindow,
                     int /* request_id */,