Clean up thread handling in Blimp browser tests.

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 c6dab89c76000bf1a2b22d07fb163d58f01df43e..d3b93f70de125aeed64a460667c97e82f82cfed9 100644
--- a/blimp/engine/mojo/blob_channel_service.cc
+++ b/blimp/engine/mojo/blob_channel_service.cc
@@ -10,24 +10,57 @@
 #include <vector>
 
 #include "base/memory/ptr_util.h"
+#include "base/task_runner_util.h"
+#include "base/threading/thread.h"
 #include "blimp/net/blob_channel/blob_channel_sender.h"
 #include "mojo/public/cpp/system/buffer.h"
 
 namespace blimp {
 namespace engine {
+namespace {
 
-BlobChannelService::BlobChannelService(BlobChannelSender* blob_channel_sender)
-    : blob_channel_sender_(blob_channel_sender) {
-  DCHECK(blob_channel_sender_);
+std::vector<BlobChannelSender::CacheStateEntry>
+GetCachedBlobIdsFromWeakPtr(base::WeakPtr<BlobChannelSender> sender) {
+  if (sender) {
+    return sender->GetCachedBlobIds();
+  } else {
+    return std::vector<BlobChannelSender::CacheStateEntry>();
+  }
+}
+
+}  // namespace
+
+BlobChannelService::BlobChannelService(
+    base::WeakPtr<BlobChannelSender> blob_channel_sender,
+    scoped_refptr<base::SingleThreadTaskRunner> blob_sender_task_runner)
+    : blob_channel_sender_(blob_channel_sender),
+      blob_sender_task_runner_(blob_sender_task_runner),
+      weak_factory_(this) {
+  DCHECK(blob_sender_task_runner_.get());
 }
 
-BlobChannelService::~BlobChannelService() {}
+BlobChannelService::~BlobChannelService() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+}
 
 void BlobChannelService::GetCachedBlobIds(
     const BlobChannelService::GetCachedBlobIdsCallback& response_callback) {
+  DCHECK(thread_checker_.CalledOnValidThread());
   VLOG(1) << "BlobChannel::GetCachedBlobIds called.";
+
+  // Pull the list of blob IDs from the UI thread.
+  base::PostTaskAndReplyWithResult(
+      blob_sender_task_runner_.get(), FROM_HERE,
+      base::Bind(&GetCachedBlobIdsFromWeakPtr, blob_channel_sender_),
+      base::Bind(&BlobChannelService::OnGetCachedBlobsCompleted,
+                 weak_factory_.GetWeakPtr(), response_callback));
+}
+
+void BlobChannelService::OnGetCachedBlobsCompleted(
+    const BlobChannelService::GetCachedBlobIdsCallback& response_callback,
+    const std::vector<BlobChannelSender::CacheStateEntry>& ids) {
   std::unordered_map<std::string, bool> cache_state;
-  for (const auto& next_entry : blob_channel_sender_->GetCachedBlobIds()) {
+  for (const auto& next_entry : ids) {
     cache_state[next_entry.id] = next_entry.was_delivered;
   }
   response_callback.Run(std::move(cache_state));
@@ -36,6 +69,8 @@ void BlobChannelService::GetCachedBlobIds(
 void BlobChannelService::PutBlob(const std::string& id,
                                  mojo::ScopedSharedBufferHandle data,
                                  uint32_t size) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
   // Map |data| into the address space and copy out its contents.
   if (!data.is_valid()) {
     LOG(ERROR) << "Invalid data handle received from renderer process.";
@@ -52,15 +87,27 @@ void BlobChannelService::PutBlob(const std::string& id,
 
   scoped_refptr<BlobData> new_blob(new BlobData);
   new_blob->data.assign(reinterpret_cast<const char*>(mapping.get()), size);
-  blob_channel_sender_->PutBlob(id, std::move(new_blob));
+
+  blob_sender_task_runner_->PostTask(FROM_HERE,
+                         base::Bind(&BlobChannelSender::PutBlob,
+                                    blob_channel_sender_,
+                                    id,
+                                    base::Passed(std::move(new_blob))));
 }
 
 void BlobChannelService::DeliverBlob(const std::string& id) {
-  blob_channel_sender_->DeliverBlob(id);
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  blob_sender_task_runner_->PostTask(FROM_HERE,
+                         base::Bind(&BlobChannelSender::DeliverBlob,
+                                    blob_channel_sender_,
+                                    id));
 }
 
 void BlobChannelService::BindRequest(
     mojo::InterfaceRequest<mojom::BlobChannel> request) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
   bindings_.AddBinding(this, std::move(request));
 }