Cleanup NativeMetafile (win) interface and EMF class.

- Rename CreateDc to Init() and remove unused argument (all non-test calls were CreateDc(NULL, NULL).  [This matches cross platform interface.]
- Remove CreateFileBackedDc from the NativeMetafile interface and make InitToFile() in the EMF class.
- Remove CreateFromFile from the NativeMetafile interface and make it InitFromFile() in the EMF class.
- Move the CloseEmf method into the destructor, making the Emf class a use once class (matches actual use).

BUG=NONE
TEST=NONE

Review URL: http://codereview.chromium.org/6695013

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@78666 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 78 insertions, 117 deletions

diff --git a/printing/emf_win.cc b/printing/emf_win.cc
index 6fea291..7e3dbeb 100644
--- a/printing/emf_win.cc
+++ b/printing/emf_win.cc
@@ -50,41 +50,39 @@ Emf::Emf() : emf_(NULL), hdc_(NULL) {
 }
 
 Emf::~Emf() {
-  CloseEmf();
-  DCHECK(!emf_ && !hdc_);
+  DCHECK(!hdc_);
+  if (emf_)
+    DeleteEnhMetaFile(emf_);
 }
 
-bool Emf::InitFromData(const void* src_buffer, uint32 src_buffer_size) {
+bool Emf::InitToFile(const FilePath& metafile_path) {
   DCHECK(!emf_ && !hdc_);
-  emf_ = SetEnhMetaFileBits(src_buffer_size,
-                            reinterpret_cast<const BYTE*>(src_buffer));
-  return emf_ != NULL;
+  hdc_ = CreateEnhMetaFile(NULL, metafile_path.value().c_str(), NULL, NULL);
+  DCHECK(hdc_);
+  return hdc_ != NULL;
 }
 
-bool Emf::CreateDc(HDC sibling, const RECT* rect) {
+bool Emf::InitFromFile(const FilePath& metafile_path) {
   DCHECK(!emf_ && !hdc_);
-  hdc_ = CreateEnhMetaFile(sibling, NULL, rect, NULL);
-  DCHECK(hdc_);
-  return hdc_ != NULL;
+  emf_ = GetEnhMetaFile(metafile_path.value().c_str());
+  DCHECK(emf_);
+  return emf_ != NULL;
 }
 
-bool Emf::CreateFileBackedDc(HDC sibling, const RECT* rect,
-                             const FilePath& path) {
+bool Emf::Init() {
   DCHECK(!emf_ && !hdc_);
-  DCHECK(!path.empty());
-  hdc_ = CreateEnhMetaFile(sibling, path.value().c_str(), rect, NULL);
+  hdc_ = CreateEnhMetaFile(NULL, NULL, NULL, NULL);
   DCHECK(hdc_);
   return hdc_ != NULL;
 }
 
-bool Emf::CreateFromFile(const FilePath& metafile_path) {
+bool Emf::InitFromData(const void* src_buffer, uint32 src_buffer_size) {
   DCHECK(!emf_ && !hdc_);
-  emf_ = GetEnhMetaFile(metafile_path.value().c_str());
-  DCHECK(emf_);
+  emf_ = SetEnhMetaFileBits(src_buffer_size,
+                            reinterpret_cast<const BYTE*>(src_buffer));
   return emf_ != NULL;
 }
 
-
 bool Emf::Close() {
   DCHECK(!emf_ && hdc_);
   emf_ = CloseEnhMetaFile(hdc_);
@@ -93,14 +91,6 @@ bool Emf::Close() {
   return emf_ != NULL;
 }
 
-void Emf::CloseEmf() {
-  DCHECK(!hdc_);
-  if (emf_) {
-    DeleteEnhMetaFile(emf_);
-    emf_ = NULL;
-  }
-}
-
 bool Emf::Playback(HDC hdc, const RECT* rect) const {
   DCHECK(emf_ && !hdc_);
   RECT bounds;
diff --git a/printing/emf_win.h b/printing/emf_win.h
index 5150356..0503e6f 100644
--- a/printing/emf_win.h
+++ b/printing/emf_win.h
@@ -27,10 +27,20 @@ class Emf : public NativeMetafile {
   class Enumerator;
   struct EnumerationContext;
 
+  // Generates a virtual HDC that will record every GDI commands and compile
+  // it in a EMF data stream.
+  Emf();
   virtual ~Emf();
 
+  // Generates a new metafile that will record every GDI command, and will
+  // be saved to |metafile_path|.
+  virtual bool InitToFile(const FilePath& metafile_path);
+
+  // Initializes the Emf with the data in |metafile_path|.
+  virtual bool InitFromFile(const FilePath& metafile_path);
+
   // NativeMetafile methods.
-  virtual bool Init() { return true; }
+  virtual bool Init();
   virtual bool InitFromData(const void* src_buffer, uint32 src_buffer_size);
 
   virtual bool StartPage();
@@ -57,14 +67,6 @@ class Emf : public NativeMetafile {
     return hdc_;
   }
 
-  virtual bool CreateDc(HDC sibling, const RECT* rect);
-  virtual bool CreateFileBackedDc(HDC sibling,
-                                  const RECT* rect,
-                                  const FilePath& path);
-  virtual bool CreateFromFile(const FilePath& file_path);
-
-  virtual void CloseEmf();
-
   virtual bool Playback(HDC hdc, const RECT* rect) const;
   virtual bool SafePlayback(HDC hdc) const;
 
@@ -74,16 +76,7 @@ class Emf : public NativeMetafile {
     return emf_;
   }
 
- protected:
-  Emf();
-
  private:
-  friend class NativeMetafileFactory;
-  FRIEND_TEST_ALL_PREFIXES(EmfTest, DC);
-  FRIEND_TEST_ALL_PREFIXES(EmfTest, FileBackedDC);
-  FRIEND_TEST_ALL_PREFIXES(EmfPrintingTest, Enumerate);
-  FRIEND_TEST_ALL_PREFIXES(EmfPrintingTest, PageBreak);
-
   // Playbacks safely one EMF record.
   static int CALLBACK SafePlaybackProc(HDC hdc,
                                        HANDLETABLE* handle_table,
diff --git a/printing/emf_win_unittest.cc b/printing/emf_win_unittest.cc
index 2f4e2ae..16ca82e 100644
--- a/printing/emf_win_unittest.cc
+++ b/printing/emf_win_unittest.cc
@@ -43,26 +43,26 @@ namespace printing {
 
 TEST(EmfTest, DC) {
   // Simplest use case.
-  printing::Emf emf;
-  RECT rect = {100, 100, 200, 200};
-  HDC hdc = CreateCompatibleDC(NULL);
-  EXPECT_TRUE(hdc != NULL);
-  EXPECT_TRUE(emf.CreateDc(hdc, &rect));
-  EXPECT_TRUE(emf.context() != NULL);
-  // In theory, you'd use the HDC with GDI functions here.
-  EXPECT_TRUE(emf.Close());
-  uint32 size = emf.GetDataSize();
-  EXPECT_EQ(size, EMF_HEADER_SIZE);
+  uint32 size;
   std::vector<BYTE> data;
-  EXPECT_TRUE(emf.GetData(&data));
-  EXPECT_EQ(data.size(), size);
-  emf.CloseEmf();
-  EXPECT_TRUE(DeleteDC(hdc));
+  {
+    printing::Emf emf;
+    EXPECT_TRUE(emf.Init());
+    EXPECT_TRUE(emf.context() != NULL);
+    // An empty EMF is invalid, so we put at least a rectangle in it.
+    ::Rectangle(emf.context(), 10, 10, 190, 190);
+    EXPECT_TRUE(emf.Close());
+    size = emf.GetDataSize();
+    EXPECT_GT(size, EMF_HEADER_SIZE);
+    EXPECT_TRUE(emf.GetData(&data));
+    EXPECT_EQ(data.size(), size);
+  }
 
   // Playback the data.
-  hdc = CreateCompatibleDC(NULL);
-  EXPECT_TRUE(hdc);
+  printing::Emf emf;
   EXPECT_TRUE(emf.InitFromData(&data.front(), size));
+  HDC hdc = CreateCompatibleDC(NULL);
+  EXPECT_TRUE(hdc);
   RECT output_rect = {0, 0, 10, 10};
   EXPECT_TRUE(emf.Playback(hdc, &output_rect));
   EXPECT_TRUE(DeleteDC(hdc));
@@ -126,28 +126,31 @@ TEST_F(EmfPrintingTest, PageBreak) {
       CreateDC(L"WINSPOOL", L"UnitTest Printer", NULL, NULL));
   if (!dc.Get())
     return;
-  printing::Emf emf;
-  EXPECT_TRUE(emf.CreateDc(dc.Get(), NULL));
-  EXPECT_TRUE(emf.context() != NULL);
-  int pages = 3;
-  while (pages) {
-    EXPECT_TRUE(emf.StartPage());
-    ::Rectangle(emf.context(), 10, 10, 190, 190);
-    EXPECT_TRUE(emf.FinishPage());
-    --pages;
-  }
-  EXPECT_TRUE(emf.Close());
-  uint32 size = emf.GetDataSize();
+  uint32 size;
   std::vector<BYTE> data;
-  EXPECT_TRUE(emf.GetData(&data));
-  EXPECT_EQ(data.size(), size);
-  emf.CloseEmf();
+  {
+    printing::Emf emf;
+    EXPECT_TRUE(emf.Init());
+    EXPECT_TRUE(emf.context() != NULL);
+    int pages = 3;
+    while (pages) {
+      EXPECT_TRUE(emf.StartPage());
+      ::Rectangle(emf.context(), 10, 10, 190, 190);
+      EXPECT_TRUE(emf.FinishPage());
+      --pages;
+    }
+    EXPECT_TRUE(emf.Close());
+    size = emf.GetDataSize();
+    EXPECT_TRUE(emf.GetData(&data));
+    EXPECT_EQ(data.size(), size);
+  }
 
   // Playback the data.
   DOCINFO di = {0};
   di.cbSize = sizeof(DOCINFO);
   di.lpszDocName = L"Test Job";
   int job_id = ::StartDoc(dc.Get(), &di);
+  printing::Emf emf;
   EXPECT_TRUE(emf.InitFromData(&data.front(), size));
   EXPECT_TRUE(emf.SafePlayback(dc.Get()));
   ::EndDoc(dc.Get());
@@ -160,41 +163,39 @@ TEST_F(EmfPrintingTest, PageBreak) {
   }
 }
 
-TEST(EmfTest, FileBackedDC) {
+TEST(EmfTest, FileBackedEmf) {
   // Simplest use case.
-  printing::Emf emf;
-  RECT rect = {100, 100, 200, 200};
-  HDC hdc = CreateCompatibleDC(NULL);
-  EXPECT_TRUE(hdc != NULL);
   ScopedTempDir scratch_metafile_dir;
   ASSERT_TRUE(scratch_metafile_dir.CreateUniqueTempDir());
   FilePath metafile_path;
   EXPECT_TRUE(file_util::CreateTemporaryFileInDir(scratch_metafile_dir.path(),
                                                   &metafile_path));
-  EXPECT_TRUE(emf.CreateFileBackedDc(hdc, &rect, metafile_path));
-  EXPECT_TRUE(emf.context() != NULL);
-  // In theory, you'd use the HDC with GDI functions here.
-  EXPECT_TRUE(emf.Close());
-
-  uint32 size = emf.GetDataSize();
-  EXPECT_EQ(size, EMF_HEADER_SIZE);
+  uint32 size;
   std::vector<BYTE> data;
-  EXPECT_TRUE(emf.GetData(&data));
-  EXPECT_EQ(data.size(), size);
-  emf.CloseEmf();
+  {
+    printing::Emf emf;
+    EXPECT_TRUE(emf.InitToFile(metafile_path));
+    EXPECT_TRUE(emf.context() != NULL);
+    // An empty EMF is invalid, so we put at least a rectangle in it.
+    ::Rectangle(emf.context(), 10, 10, 190, 190);
+    EXPECT_TRUE(emf.Close());
+    size = emf.GetDataSize();
+    EXPECT_GT(size, EMF_HEADER_SIZE);
+    EXPECT_TRUE(emf.GetData(&data));
+    EXPECT_EQ(data.size(), size);
+  }
   int64 file_size = 0;
   file_util::GetFileSize(metafile_path, &file_size);
   EXPECT_EQ(size, file_size);
-  EXPECT_TRUE(DeleteDC(hdc));
 
   // Playback the data.
-  hdc = CreateCompatibleDC(NULL);
+  HDC hdc = CreateCompatibleDC(NULL);
   EXPECT_TRUE(hdc);
-  EXPECT_TRUE(emf.CreateFromFile(metafile_path));
+  printing::Emf emf;
+  EXPECT_TRUE(emf.InitFromFile(metafile_path));
   RECT output_rect = {0, 0, 10, 10};
   EXPECT_TRUE(emf.Playback(hdc, &output_rect));
   EXPECT_TRUE(DeleteDC(hdc));
-  emf.CloseEmf();
 }
 
 }  // namespace printing
diff --git a/printing/native_metafile.h b/printing/native_metafile.h
index a076b32..08b3277 100644
--- a/printing/native_metafile.h
+++ b/printing/native_metafile.h
@@ -101,29 +101,6 @@ class NativeMetafile {
   virtual gfx::NativeDrawingContext context() const = 0;
 
 #if defined(OS_WIN)
-  // Generates a virtual HDC that will record every GDI commands and compile it
-  // in a EMF data stream.
-  // hdc is used to setup the default DPI and color settings. hdc is optional.
-  // rect specifies the dimensions (in .01-millimeter units) of the EMF. rect is
-  // optional.
-  virtual bool CreateDc(gfx::NativeDrawingContext sibling,
-                        const RECT* rect) = 0;
-
-  // Similar to the above method but the metafile is backed by a file.
-  virtual bool CreateFileBackedDc(gfx::NativeDrawingContext sibling,
-                                  const RECT* rect,
-                                  const FilePath& path) = 0;
-
-  // TODO(maruel): CreateFromFile(). If ever used. Maybe users would like to
-  // have the ability to save web pages to an EMF file? Afterward, it is easy to
-  // convert to PDF or PS.
-  // Load a metafile fromdisk.
-  virtual bool CreateFromFile(const FilePath& metafile_path) = 0;
-
-  // Closes the HDC created by CreateDc() and generates the compiled EMF
-  // data.
-  virtual void CloseEmf() = 0;
-
   // "Plays" the EMF buffer in a HDC. It is the same effect as calling the
   // original GDI function that were called when recording the EMF. |rect| is in
   // "logical units" and is optional. If |rect| is NULL, the natural EMF bounds