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..7e0d740007bf9b0c4af82f8e96bb70f84a799c43 100644
--- a/blimp/engine/mojo/blob_channel_service.cc
+++ b/blimp/engine/mojo/blob_channel_service.cc
@@ -4,6 +4,8 @@
 
 #include "blimp/engine/mojo/blob_channel_service.h"
 
+#include <vector>
+
 #include "blimp/net/blob_channel/blob_channel_sender.h"
 
 namespace blimp {
@@ -18,6 +20,24 @@ BlobChannelService::BlobChannelService(BlobChannelSender* blob_channel_sender,
 
 BlobChannelService::~BlobChannelService() {}
 
+void BlobChannelService::GetCacheState(
+    const BlobChannelService::GetCacheStateCallback& callback) {
+  VLOG(1) << "BlobChannel::GetCacheState called.";
+
+  // Get the cache state & marshal the contents to the Mojo response.

[Wez, 2016/06/21 00:33:33]

"marshal the contents to ... response" sounds odd - you mean just pass them to
the |callback|?

[Kevin M, 2016/06/21 21:23:51]

Done.

+  std::vector<BlobChannelSender::CacheState> cache_state =
+      blob_channel_sender_->GetCacheState();
+  auto output = mojo::Array<mojom::CacheStateEntryPtr>::New(cache_state.size());
+  for (size_t i = 0; i < cache_state.size(); ++i) {
+    mojom::CacheStateEntryPtr converted(mojom::CacheStateEntry::New());
+    converted->id = cache_state[i].id;
+    converted->is_replicated = cache_state[i].is_replicated;
+    output[i] = std::move(converted);
+  }
+
+  callback.Run(std::move(output));
+}
+
 void BlobChannelService::PutBlob(const mojo::String& id,
                                  const mojo::String& data) {
   blob_channel_sender_->PutBlob(id, new BlobData(data));