Convert printing IPCs to Mojo

chrome/browser/printing/pdf_to_emf_converter.cc

Index: chrome/browser/printing/pdf_to_emf_converter.cc
diff --git a/chrome/browser/printing/pdf_to_emf_converter.cc b/chrome/browser/printing/pdf_to_emf_converter.cc
index fb0be329e76d0325e4b0c20645adf832fb1d3303..e6277cc57c9dd3c0efc0e5beec2abdf5d73cd78c 100644
--- a/chrome/browser/printing/pdf_to_emf_converter.cc
+++ b/chrome/browser/printing/pdf_to_emf_converter.cc
@@ -12,6 +12,7 @@
 #include <utility>
 #include <vector>
 
+#include "base/callback_helpers.h"
 #include "base/files/file.h"
 #include "base/files/file_util.h"
 #include "base/files/scoped_temp_dir.h"
@@ -20,14 +21,15 @@
 #include "base/memory/ptr_util.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "chrome/common/chrome_utility_messages.h"
-#include "chrome/common/chrome_utility_printing_messages.h"
 #include "chrome/grit/generated_resources.h"
+#include "components/printing/common/printing.mojom.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/child_process_data.h"
-#include "content/public/browser/utility_process_host.h"
-#include "content/public/browser/utility_process_host_client.h"
+#include "content/public/browser/utility_process_mojo_client.h"
+#include "mojo/public/cpp/bindings/strong_binding.h"
 #include "printing/emf_win.h"
 #include "printing/pdf_render_settings.h"
+#include "services/service_manager/public/cpp/interface_provider.h"
 #include "ui/base/l10n/l10n_util.h"
 
 namespace printing {
@@ -89,11 +91,11 @@ class LazyEmf : public MetafilePlayer {
 };
 
 // Converts PDF into EMF.
-// Class uses 3 threads: UI, IO and FILE.
+// Class uses 2 threads: UI and FILE.
 // Internal workflow is following:
 // 1. Create instance on the UI thread. (files_, settings_,)
 // 2. Create pdf file on the FILE thread.
-// 3. Start utility process and start conversion on the IO thread.
+// 3. Start utility process and start conversion on the UI thread.
 // 4. Utility process returns page count.
 // 5. For each page:
 //   1. Clients requests page with file handle to a temp file.
@@ -102,7 +104,7 @@ class LazyEmf : public MetafilePlayer {
 // All these steps work sequentially, so no data should be accessed
 // simultaneously by several threads.
 class PdfToEmfUtilityProcessHostClient
-    : public content::UtilityProcessHostClient {
+    : public base::RefCountedThreadSafe<PdfToEmfUtilityProcessHostClient> {
  public:
   PdfToEmfUtilityProcessHostClient(
       base::WeakPtr<PdfToEmfConverterImpl> converter,
@@ -117,15 +119,6 @@ class PdfToEmfUtilityProcessHostClient
 
   void Stop();
 
-  // Needs to be public to handle ChromeUtilityHostMsg_PreCacheFontCharacters
-  // sync message replies.
-  bool Send(IPC::Message* msg);
-
-  // UtilityProcessHostClient implementation.
-  void OnProcessCrashed(int exit_code) override;
-  void OnProcessLaunchFailed(int exit_code) override;
-  bool OnMessageReceived(const IPC::Message& message) override;
-
  private:
   class GetPageCallbackData {
    public:
@@ -159,13 +152,12 @@ class PdfToEmfUtilityProcessHostClient
     DISALLOW_COPY_AND_ASSIGN(GetPageCallbackData);
   };
 
-  ~PdfToEmfUtilityProcessHostClient() override;
+  friend class base::RefCountedThreadSafe<PdfToEmfUtilityProcessHostClient>;
+  ~PdfToEmfUtilityProcessHostClient();
 
   // Message handlers.
   void OnPageCount(int page_count);
   void OnPageDone(bool success, float scale_factor);
-  void OnPreCacheFontCharacters(const LOGFONT& log_font,
-                                const base::string16& characters);
 
   void OnFailed();
   void OnTempPdfReady(bool print_text_with_gdi, ScopedTempFile pdf);
@@ -180,8 +172,8 @@ class PdfToEmfUtilityProcessHostClient
   // Document loaded callback.
   PdfToEmfConverter::StartCallback start_callback_;
 
-  // Process host for IPC.
-  base::WeakPtr<content::UtilityProcessHost> utility_process_host_;
+  std::unique_ptr<content::UtilityProcessMojoClient<mojom::PrintingFactory>>
+      utility_client_;
 
   // Queue of callbacks for GetPage() requests. Utility process should reply
   // with PageDone in the same order as requests were received.
@@ -189,6 +181,9 @@ class PdfToEmfUtilityProcessHostClient
   typedef std::queue<GetPageCallbackData> GetPageCallbacks;
   GetPageCallbacks get_page_callbacks_;
 
+  // Bound and used on the UI thread.
+  mojom::PrintingPtr printing_;
+
   DISALLOW_COPY_AND_ASSIGN(PdfToEmfUtilityProcessHostClient);
 };
 
@@ -297,23 +292,74 @@ bool LazyEmf::LoadEmf(Emf* emf) const {
 PdfToEmfUtilityProcessHostClient::PdfToEmfUtilityProcessHostClient(
     base::WeakPtr<PdfToEmfConverterImpl> converter,
     const PdfRenderSettings& settings)
-    : converter_(converter), settings_(settings) {
-}
+    : converter_(converter), settings_(settings) {}
 
 PdfToEmfUtilityProcessHostClient::~PdfToEmfUtilityProcessHostClient() {
 }
 
+class FontPreCachingImpl : public mojom::FontPreCaching {
+ public:
+  FontPreCachingImpl() = default;
+  ~FontPreCachingImpl() override = default;
+
+  static void Create(mojom::FontPreCachingRequest request);
+
+  // mojom::FontPreCaching:
+  void PreCacheFontCharacters(
+      const LOGFONT& log_font,
+      const base::string16& characters,
+      const PreCacheFontCharactersCallback& callback) override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(FontPreCachingImpl);
+};
+
+void FontPreCachingImpl::Create(mojom::FontPreCachingRequest request) {
+  mojo::MakeStrongBinding(base::MakeUnique<FontPreCachingImpl>(),
+                          std::move(request));
+}
+
+void FontPreCachingImpl::PreCacheFontCharacters(
+    const LOGFONT& font,
+    const base::string16& str,
+    const PreCacheFontCharactersCallback& callback) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+
+  // TODO(scottmg): pdf/ppapi still require the renderer to be able to precache
+  // GDI fonts (http://crbug.com/383227), even when using DirectWrite.
+  // Eventually this shouldn't be added and should be moved to
+  // FontCacheDispatcher too. http://crbug.com/356346.
+
+  // First, comments from FontCacheDispatcher::OnPreCacheFont do apply here too.
+  // Except that for True Type fonts,
+  // GetTextMetrics will not load the font in memory.
+  // The only way windows seem to load properly, it is to create a similar
+  // device (like the one in which we print), then do an ExtTextOut,
+  // as we do in the printing thread, which is sandboxed.
+  HDC hdc = CreateEnhMetaFile(nullptr, nullptr, nullptr, nullptr);
+  HFONT font_handle = CreateFontIndirect(&font);
+  DCHECK(font_handle != nullptr);
+
+  HGDIOBJ old_font = SelectObject(hdc, font_handle);
+  DCHECK(old_font != nullptr);
+
+  ExtTextOut(hdc, 0, 0, ETO_GLYPH_INDEX, 0, str.c_str(), str.length(), nullptr);
+
+  SelectObject(hdc, old_font);
+  DeleteObject(font_handle);
+
+  HENHMETAFILE metafile = CloseEnhMetaFile(hdc);
+
+  if (metafile)
+    DeleteEnhMetaFile(metafile);
+  callback.Run();
+}
+
 void PdfToEmfUtilityProcessHostClient::Start(
     const scoped_refptr<base::RefCountedMemory>& data,
     bool print_text_with_gdi,
     const PdfToEmfConverter::StartCallback& start_callback) {
-  if (!BrowserThread::CurrentlyOn(BrowserThread::IO)) {
-    BrowserThread::PostTask(
-        BrowserThread::IO, FROM_HERE,
-        base::Bind(&PdfToEmfUtilityProcessHostClient::Start, this, data,
-                   print_text_with_gdi, start_callback));
-    return;
-  }
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   // Store callback before any OnFailed() call to make it called on failure.
   start_callback_ = start_callback;
@@ -321,11 +367,19 @@ void PdfToEmfUtilityProcessHostClient::Start(
   // NOTE: This process _must_ be sandboxed, otherwise the pdf dll will load
   // gdiplus.dll, change how rendering happens, and not be able to correctly
   // generate when sent to a metafile DC.
-  utility_process_host_ = content::UtilityProcessHost::Create(
-                              this, base::ThreadTaskRunnerHandle::Get())
-                              ->AsWeakPtr();
-  utility_process_host_->SetName(l10n_util::GetStringUTF16(
-      IDS_UTILITY_PROCESS_EMF_CONVERTOR_NAME));
+  utility_client_ = base::MakeUnique<
+      content::UtilityProcessMojoClient<mojom::PrintingFactory>>(
+      l10n_util::GetStringUTF16(IDS_UTILITY_PROCESS_EMF_CONVERTOR_NAME));
+  utility_client_->set_error_callback(
+      base::Bind(&PdfToEmfUtilityProcessHostClient::OnFailed, this));
+  utility_client_->Start();
+  mojom::FontPreCachingPtr font_precaching;
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      base::Bind(&FontPreCachingImpl::Create,
+                 base::Passed(mojo::MakeRequest(&font_precaching))));
+  utility_client_->service()->MakePrinting(mojo::MakeRequest(&printing_),
+                                           std::move(font_precaching));
 
   BrowserThread::PostTaskAndReplyWithResult(
       BrowserThread::FILE, FROM_HERE,
@@ -336,45 +390,30 @@ void PdfToEmfUtilityProcessHostClient::Start(
 
 void PdfToEmfUtilityProcessHostClient::OnTempPdfReady(bool print_text_with_gdi,
                                                       ScopedTempFile pdf) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  if (!utility_process_host_ || !pdf)
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  if (!utility_client_ || !pdf)
     return OnFailed();
-  // Should reply with OnPageCount().
-  Send(new ChromeUtilityMsg_RenderPDFPagesToMetafiles(
-      IPC::GetPlatformFileForTransit(pdf->GetPlatformFile(), false), settings_,
-      print_text_with_gdi));
+  printing_->RenderPDFPagesToMetafiles(
+      pdf->Duplicate(), settings_, print_text_with_gdi,
+      base::Bind(&PdfToEmfUtilityProcessHostClient::OnPageCount, this));
 }
 
 void PdfToEmfUtilityProcessHostClient::OnPageCount(int page_count) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
   if (start_callback_.is_null())
     return OnFailed();
-  BrowserThread::PostTask(BrowserThread::UI,
-                          FROM_HERE,
-                          base::Bind(&PdfToEmfConverterImpl::RunCallback,
-                                     converter_,
-                                     base::Bind(start_callback_, page_count)));
-  start_callback_.Reset();
+  base::ResetAndReturn(&start_callback_).Run(page_count);
 }
 
 void PdfToEmfUtilityProcessHostClient::GetPage(
     int page_number,
     const PdfToEmfConverter::GetPageCallback& get_page_callback) {
-  if (!BrowserThread::CurrentlyOn(BrowserThread::IO)) {
-    BrowserThread::PostTask(
-        BrowserThread::IO,
-        FROM_HERE,
-        base::Bind(&PdfToEmfUtilityProcessHostClient::GetPage,
-                   this,
-                   page_number,
-                   get_page_callback));
-    return;
-  }
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   // Store callback before any OnFailed() call to make it called on failure.
   get_page_callbacks_.push(GetPageCallbackData(page_number, get_page_callback));
 
-  if (!utility_process_host_)
+  if (!utility_client_)
     return OnFailed();
 
   BrowserThread::PostTaskAndReplyWithResult(
@@ -389,20 +428,18 @@ void PdfToEmfUtilityProcessHostClient::GetPage(
 void PdfToEmfUtilityProcessHostClient::OnTempEmfReady(
     GetPageCallbackData* callback_data,
     ScopedTempFile emf) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  if (!utility_process_host_ || !emf)
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  if (!utility_client_ || !emf)
     return OnFailed();
-  IPC::PlatformFileForTransit transit =
-      IPC::GetPlatformFileForTransit(emf->GetPlatformFile(), false);
   callback_data->set_emf(std::move(emf));
-  // Should reply with OnPageDone().
-  Send(new ChromeUtilityMsg_RenderPDFPagesToMetafiles_GetPage(
-      callback_data->page_number(), transit));
+  printing_->RenderPDFPagesToMetafilesGetPage(
+      callback_data->page_number(), emf->Duplicate(),
+      base::Bind(&PdfToEmfUtilityProcessHostClient::OnPageDone, this));
 }
 
 void PdfToEmfUtilityProcessHostClient::OnPageDone(bool success,
                                                   float scale_factor) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
   if (get_page_callbacks_.empty())
     return OnFailed();
   GetPageCallbackData& data = get_page_callbacks_.front();
@@ -415,97 +452,22 @@ void PdfToEmfUtilityProcessHostClient::OnPageDone(bool success,
     emf = base::MakeUnique<LazyEmf>(temp_dir_, std::move(temp_emf));
   }
 
-  BrowserThread::PostTask(BrowserThread::UI,
-                          FROM_HERE,
-                          base::Bind(&PdfToEmfConverterImpl::RunCallback,
-                                     converter_,
-                                     base::Bind(data.callback(),
-                                                data.page_number(),
-                                                scale_factor,
-                                                base::Passed(&emf))));
+  data.callback().Run(data.page_number(), scale_factor, std::move(emf));
   get_page_callbacks_.pop();
 }
 
-void PdfToEmfUtilityProcessHostClient::OnPreCacheFontCharacters(
-    const LOGFONT& font,
-    const base::string16& str) {
-  // TODO(scottmg): pdf/ppapi still require the renderer to be able to precache
-  // GDI fonts (http://crbug.com/383227), even when using DirectWrite.
-  // Eventually this shouldn't be added and should be moved to
-  // FontCacheDispatcher too. http://crbug.com/356346.
-
-  // First, comments from FontCacheDispatcher::OnPreCacheFont do apply here too.
-  // Except that for True Type fonts,
-  // GetTextMetrics will not load the font in memory.
-  // The only way windows seem to load properly, it is to create a similar
-  // device (like the one in which we print), then do an ExtTextOut,
-  // as we do in the printing thread, which is sandboxed.
-  HDC hdc = CreateEnhMetaFile(nullptr, nullptr, nullptr, nullptr);
-  HFONT font_handle = CreateFontIndirect(&font);
-  DCHECK(font_handle != nullptr);
-
-  HGDIOBJ old_font = SelectObject(hdc, font_handle);
-  DCHECK(old_font != nullptr);
-
-  ExtTextOut(hdc, 0, 0, ETO_GLYPH_INDEX, 0, str.c_str(), str.length(), nullptr);
-
-  SelectObject(hdc, old_font);
-  DeleteObject(font_handle);
-
-  HENHMETAFILE metafile = CloseEnhMetaFile(hdc);
-
-  if (metafile)
-    DeleteEnhMetaFile(metafile);
-}
-
 void PdfToEmfUtilityProcessHostClient::Stop() {
-  if (!BrowserThread::CurrentlyOn(BrowserThread::IO)) {
-    BrowserThread::PostTask(
-        BrowserThread::IO,
-        FROM_HERE,
-        base::Bind(&PdfToEmfUtilityProcessHostClient::Stop, this));
-    return;
-  }
-  Send(new ChromeUtilityMsg_RenderPDFPagesToMetafiles_Stop());
-}
-
-void PdfToEmfUtilityProcessHostClient::OnProcessCrashed(int exit_code) {
-  OnFailed();
-}
-
-void PdfToEmfUtilityProcessHostClient::OnProcessLaunchFailed(int exit_code) {
-  OnFailed();
-}
-
-bool PdfToEmfUtilityProcessHostClient::OnMessageReceived(
-    const IPC::Message& message) {
-  bool handled = true;
-  IPC_BEGIN_MESSAGE_MAP(PdfToEmfUtilityProcessHostClient, message)
-    IPC_MESSAGE_HANDLER(
-        ChromeUtilityHostMsg_RenderPDFPagesToMetafiles_PageCount, OnPageCount)
-    IPC_MESSAGE_HANDLER(ChromeUtilityHostMsg_RenderPDFPagesToMetafiles_PageDone,
-                        OnPageDone)
-    IPC_MESSAGE_HANDLER(ChromeUtilityHostMsg_PreCacheFontCharacters,
-                        OnPreCacheFontCharacters)
-    IPC_MESSAGE_UNHANDLED(handled = false)
-  IPC_END_MESSAGE_MAP()
-  return handled;
-}
-
-bool PdfToEmfUtilityProcessHostClient::Send(IPC::Message* msg) {
-  if (utility_process_host_)
-    return utility_process_host_->Send(msg);
-  delete msg;
-  return false;
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  printing_.reset();
 }
 
 void PdfToEmfUtilityProcessHostClient::OnFailed() {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
   if (!start_callback_.is_null())
     OnPageCount(0);
   while (!get_page_callbacks_.empty())
     OnPageDone(false, 0.0f);
-  utility_process_host_.reset();
+  utility_client_.reset();
 }
 
 PdfToEmfConverterImpl::PdfToEmfConverterImpl() : weak_ptr_factory_(this) {