Use pdf compositor service for printing when OOPIF is enabled

components/printing/browser/print_composite_client.cc

Index: components/printing/browser/print_composite_client.cc
diff --git a/components/printing/browser/print_composite_client.cc b/components/printing/browser/print_composite_client.cc
new file mode 100644
index 0000000000000000000000000000000000000000..5516ccc35d479784ab06a4680a82b7322642026f
--- /dev/null
+++ b/components/printing/browser/print_composite_client.cc
@@ -0,0 +1,83 @@
+// 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.
+
+#include "components/printing/browser/print_composite_client.h"
+
+#include <memory>
+#include <utility>
+
+#include "base/threading/thread_task_runner_handle.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/common/service_manager_connection.h"
+#include "mojo/public/cpp/system/platform_handle.h"
+#include "services/service_manager/public/cpp/connector.h"
+
+DEFINE_WEB_CONTENTS_USER_DATA_KEY(printing::PrintCompositeClient);
+
+namespace printing {
+
+PrintCompositeClient::PrintCompositeClient(content::WebContents* web_contents) {
+}
+
+PrintCompositeClient::~PrintCompositeClient() {}
+
+void PrintCompositeClient::CreateConnectorRequest() {
+  connector_ = service_manager::Connector::Create(&connector_request_);
+  content::ServiceManagerConnection::GetForProcess()
+      ->GetConnector()
+      ->BindConnectorRequest(std::move(connector_request_));
+}
+
+void PrintCompositeClient::DoComposite(
+    base::SharedMemoryHandle handle,
+    uint32_t data_size,
+    mojom::PdfCompositor::CompositePdfCallback callback) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  DCHECK(data_size);

[Lei Zhang, 2017/09/09 00:44:59]

With the DCHECK, I'm worried the call from
PrintViewManagerBase::OnDidPrintPage() can potentially cause this to fail, since
it doesn't check for empty data. The print_preview_message_handler.cc callers do
check.

+
+  if (!connector_)
+    CreateConnectorRequest();
+  Composite(connector_.get(), handle, data_size, std::move(callback),
+            base::ThreadTaskRunnerHandle::Get());
+}
+
+std::unique_ptr<base::SharedMemory> PrintCompositeClient::GetShmFromMojoHandle(
+    mojo::ScopedSharedBufferHandle handle) {
+  if (!handle.is_valid()) {
+    DLOG(ERROR) << "Invalid mojo handle.";
+    return nullptr;
+  }
+
+  base::SharedMemoryHandle memory_handle;
+  size_t memory_size = 0;
+  bool read_only_flag = false;
+
+  const MojoResult result = mojo::UnwrapSharedMemoryHandle(
+      std::move(handle), &memory_handle, &memory_size, &read_only_flag);
+  DCHECK_EQ(MOJO_RESULT_OK, result);
+  DCHECK_GT(memory_size, 0u);
+
+  std::unique_ptr<base::SharedMemory> shm =
+      base::MakeUnique<base::SharedMemory>(memory_handle, true /* read_only */);
+  if (!shm->Map(memory_size)) {
+    DLOG(ERROR) << "Map shared memory failed.";
+    return nullptr;
+  }
+  return shm;
+}
+
+scoped_refptr<base::RefCountedBytes>
+PrintCompositeClient::GetDataFromMojoHandle(
+    mojo::ScopedSharedBufferHandle handle) {
+  std::unique_ptr<base::SharedMemory> shm =
+      GetShmFromMojoHandle(std::move(handle));
+  if (!shm)
+    return nullptr;
+
+  return base::MakeRefCounted<base::RefCountedBytes>(
+      reinterpret_cast<const unsigned char*>(shm->memory()),
+      shm->mapped_size());
+}
+
+}  // namespace printing