Use pdf compositor service for printing when OOPIF is enabled

components/printing/browser/print_composite_client.h

Index: components/printing/browser/print_composite_client.h
diff --git a/components/printing/browser/print_composite_client.h b/components/printing/browser/print_composite_client.h
new file mode 100644
index 0000000000000000000000000000000000000000..3bf4c8dfd6732caf97dc3addfd2fa885eb120585
--- /dev/null
+++ b/components/printing/browser/print_composite_client.h
@@ -0,0 +1,49 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef COMPONENTS_PRINTING_BROWSER_PRINT_COMPOSITE_CLIENT_H_
+#define COMPONENTS_PRINTING_BROWSER_PRINT_COMPOSITE_CLIENT_H_
+
+#include "base/memory/ref_counted_memory.h"
+#include "base/memory/shared_memory.h"
+#include "base/memory/shared_memory_handle.h"
+#include "base/sequenced_task_runner.h"
+#include "components/printing/service/public/cpp/pdf_compositor_client.h"
+#include "content/public/browser/web_contents_observer.h"
+#include "content/public/browser/web_contents_user_data.h"
+
+namespace printing {
+
+class PrintCompositeClient
+    : public PdfCompositorClient,
+      public content::WebContentsObserver,
+      public content::WebContentsUserData<PrintCompositeClient> {
+ public:
+  explicit PrintCompositeClient(content::WebContents* web_contents);
+  ~PrintCompositeClient() override;
+
+  void CreateConnectorRequest();
+  void DoComposite(
+      base::SharedMemoryHandle handle,
+      uint32_t data_size,
+      mojom::PdfCompositor::CompositePdfCallback callback,
+      scoped_refptr<base::SequencedTaskRunner> callback_task_runner);

[Lei Zhang, 2017/08/28 23:01:13]

Is this always going to be UI thread?

[Wei Li, 2017/08/30 00:24:03]

Yes, so far all the callers are from UI thread. But this function is not tied to
UI thread.

[Lei Zhang, 2017/08/30 02:00:35]

Is it reasonable to make DoComposite() just reply on the task runner it was
called on?

[Wei Li, 2017/08/31 21:00:25]

Sounds good, done.

+
+  // Utility functions.
+  static std::unique_ptr<base::SharedMemory> GetShmFromMojoHandle(
+      mojo::ScopedSharedBufferHandle handle);
+  static scoped_refptr<base::RefCountedBytes> GetDataFromMojoHandle(
+      mojo::ScopedSharedBufferHandle handle);
+
+ private:
+  service_manager::mojom::ConnectorRequest connector_request_;
+  std::unique_ptr<service_manager::Connector> connector_;
+  base::WeakPtrFactory<PrintCompositeClient> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(PrintCompositeClient);
+};
+
+}  // namespace printing
+
+#endif  // COMPONENTS_PRINTING_BROWSER_PRINT_COMPOSITE_CLIENT_H_