Add Mojo IPC for seeding new Renderer with Browser's cached blob state.

blimp/engine/mojo/blob_channel_service.cc

Index: blimp/engine/mojo/blob_channel_service.cc
diff --git a/blimp/engine/mojo/blob_channel_service.cc b/blimp/engine/mojo/blob_channel_service.cc
index 0234df60698b3a2c2628537b7e66cfd9ae44bfd9..043c961b22eea033c15c106d6ff5574f45257e82 100644
--- a/blimp/engine/mojo/blob_channel_service.cc
+++ b/blimp/engine/mojo/blob_channel_service.cc
@@ -4,6 +4,9 @@
 
 #include "blimp/engine/mojo/blob_channel_service.h"
 
+#include <vector>
+
+#include "base/memory/ptr_util.h"
 #include "blimp/net/blob_channel/blob_channel_sender.h"
 
 namespace blimp {
@@ -18,6 +21,16 @@ BlobChannelService::BlobChannelService(BlobChannelSender* blob_channel_sender,
 
 BlobChannelService::~BlobChannelService() {}
 
+void BlobChannelService::GetCachedBlobIds(
+    const BlobChannelService::GetCachedBlobIdsCallback& callback) {

[Wez, 2016/07/01 00:30:20]

nit: |callback| seems unnecessarily generic - this is specifically the
"response" callback, so maybe call it "respond" or "response_callback"?

[Kevin M, 2016/07/18 16:58:16]

Done.

+  VLOG(1) << "BlobChannel::GetCachedBlobIds called.";
+  mojo::Map<mojo::String, bool> output;

[Wez, 2016/07/01 00:30:20]

nit: cache_state, for consistency w/ other call sites?

[Kevin M, 2016/07/18 16:58:16]

Done.

+  for (const auto& next_entry : blob_channel_sender_->GetCachedBlobIds()) {
+    output[next_entry.id] = next_entry.was_delivered;
+  }
+  callback.Run(std::move(output));
+}
+
 void BlobChannelService::PutBlob(const mojo::String& id,
                                  const mojo::String& data) {
   blob_channel_sender_->PutBlob(id, new BlobData(data));