Turn the utility process image decoder into a Mojo service.

chrome/utility/chrome_content_utility_client.cc

Index: chrome/utility/chrome_content_utility_client.cc
diff --git a/chrome/utility/chrome_content_utility_client.cc b/chrome/utility/chrome_content_utility_client.cc
index d82c23bf5479e1b7cf85f27b64a0953c7d635c47..4e1058afef5e0d240af30a3e34e3a716c56bc009 100644
--- a/chrome/utility/chrome_content_utility_client.cc
+++ b/chrome/utility/chrome_content_utility_client.cc
@@ -20,6 +20,7 @@
 #include "courgette/courgette.h"
 #include "courgette/third_party/bsdiff.h"
 #include "ipc/ipc_channel.h"
+#include "services/image_decoder/services/image_decoder_impl.h"
 #include "skia/ext/image_operations.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/zlib/google/zip.h"
@@ -84,13 +85,43 @@ void CreateProxyResolverFactory(
 }
 #endif  // OS_ANDROID
 
+// A simple Mojo service wrapper that reference counts this utility process.
+template <class Impl, class Request>
+class RefCountingMojoService : public Impl {
+ public:
+  RefCountingMojoService(ChromeContentUtilityClient* utility_client,
+                         Request req)
+      : Impl(req.Pass()),
+        utility_client_(utility_client) {
+    DCHECK(utility_client);
+    utility_client_->MojoRef();
+  }
+  ~RefCountingMojoService() override {
+    utility_client_->MojoUnref();
+  }
+
+ private:
+  ChromeContentUtilityClient* utility_client_;
+};
+
+template <class Interface, class Impl>
+void CreateMojoService(ChromeContentUtilityClient* utility_client,
+                       mojo::InterfaceRequest<Interface> request) {
+  // The Mojo service implementation is assumed to use a StrongBinding<>, which
+  // causes the implementation to be deleted automatically when the Mojo
+  // connection is closed.
+  new RefCountingMojoService<Impl, mojo::InterfaceRequest<Interface>>(
+      utility_client, request.Pass());
+}
+
 }  // namespace
 
 int64_t ChromeContentUtilityClient::max_ipc_message_size_ =
     IPC::Channel::kMaximumMessageSize;
 
 ChromeContentUtilityClient::ChromeContentUtilityClient()
-    : filter_messages_(false) {
+    : filter_messages_(false),
+      mojo_service_ref_count_(0) {
 #if !defined(OS_ANDROID)
   handlers_.push_back(new ProfileImportHandler());
 #endif
@@ -179,6 +210,27 @@ void ChromeContentUtilityClient::RegisterMojoServices(
   registry->AddService<net::interfaces::ProxyResolverFactory>(
       base::Bind(CreateProxyResolverFactory));
 #endif
+  registry->AddService<services::image_decoder::ImageDecoder>(
+      base::Bind(
+          CreateMojoService<services::image_decoder::ImageDecoder,
+                            services::image_decoder::ImageDecoderImpl>,
+          this));
+}
+
+void ChromeContentUtilityClient::MojoRef() {
+  LOG(INFO) << "ChromeContentUtilityClient::MojoRef";
+  mojo_service_ref_count_++;
+  DCHECK_GT(mojo_service_ref_count_, 0);
+}
+
+void ChromeContentUtilityClient::MojoUnref() {
+  LOG(INFO) << "ChromeContentUtilityClient::MojoUnref";
+  DCHECK_GT(mojo_service_ref_count_, 0);
+  mojo_service_ref_count_--;
+  if (mojo_service_ref_count_ <= 0) {
+    LOG(INFO) << "Releasing Mojo process";
+    ReleaseProcessIfNeeded();
+  }
 }
 
 // static