Unifying NativeMetafile class interface (as much as possible) for Linux, Mac, Win

printing/pdf_metafile_mac.cc

 // Copyright (c) 2009 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 "printing/pdf_metafile_mac.h"
 
 #include "base/file_path.h"
 #include "base/logging.h"
 #include "base/mac/scoped_cftyperef.h"
 #include "base/sys_string_conversions.h"
 #include "ui/gfx/rect.h"
 
 using base::mac::ScopedCFTypeRef;
 
 namespace printing {
 
 PdfMetafile::PdfMetafile()
     : page_is_open_(false) {
 }
 
 PdfMetafile::~PdfMetafile() {}
 
-CGContextRef PdfMetafile::Init() {
+bool PdfMetafile::Init() {
   // Ensure that Init hasn't already been called.
   DCHECK(!context_.get());
   DCHECK(!pdf_data_.get());
 
   pdf_data_.reset(CFDataCreateMutable(kCFAllocatorDefault, 0));
   if (!pdf_data_.get()) {
     LOG(ERROR) << "Failed to create pdf data for metafile";
-    return NULL;
+    return false;
   }
   ScopedCFTypeRef<CGDataConsumerRef> pdf_consumer(
       CGDataConsumerCreateWithCFData(pdf_data_));
   if (!pdf_consumer.get()) {
     LOG(ERROR) << "Failed to create data consumer for metafile";
     pdf_data_.reset(NULL);
-    return NULL;
+    return false;
   }
   context_.reset(CGPDFContextCreate(pdf_consumer, NULL, NULL));
   if (!context_.get()) {
     LOG(ERROR) << "Failed to create pdf context for metafile";
     pdf_data_.reset(NULL);
   }
 
-  return context_.get();
+  return true;
 }
 
 bool PdfMetafile::Init(const void* src_buffer, uint32 src_buffer_size) {
   DCHECK(!context_.get());
   DCHECK(!pdf_data_.get());
 
   if (!src_buffer || src_buffer_size == 0) {
     return false;
   }
 
@@ skipping 20 matching lines @@
   // Flip the context.
   CGContextTranslateCTM(context_, 0, height);
   CGContextScaleCTM(context_, scale_factor, -scale_factor);
 
   // Move the context to origin.
   CGContextTranslateCTM(context_, content_origin.x(), content_origin.y());
 
   return context_.get();
 }
 
-void PdfMetafile::FinishPage() {
+bool PdfMetafile::FinishPage() {
   DCHECK(context_.get());
   DCHECK(page_is_open_);
 
   CGContextRestoreGState(context_);
   CGContextEndPage(context_);
   page_is_open_ = false;
+  return true;
 }
 
 void PdfMetafile::Close() {
   DCHECK(context_.get());
   DCHECK(!page_is_open_);
 
 #ifndef NDEBUG
   // Check that the context will be torn down properly; if it's not, pdf_data_
   // will be incomplete and generate invalid PDF files/documents.
   if (context_.get()) {
@@ skipping 126 matching lines @@
 
   if (!pdf_doc_.get()) {
     ScopedCFTypeRef<CGDataProviderRef> pdf_data_provider(
         CGDataProviderCreateWithCFData(pdf_data_));
     pdf_doc_.reset(CGPDFDocumentCreateWithProvider(pdf_data_provider));
   }
   return pdf_doc_.get();
 }
 
 }  // namespace printing