Assert on BeginPlatformPaint/EndPlatformPaint mismatch.

skia/ext/bitmap_platform_device_win.cc

 // Copyright (c) 2011 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 <windows.h>
 #include <psapi.h>
 
 #include "skia/ext/bitmap_platform_device_win.h"
 
 #include "skia/ext/bitmap_platform_device_data.h"
@@ skipping 159 matching lines @@
 }
 
 // The device will own the HBITMAP, which corresponds to also owning the pixel
 // data. Therefore, we do not transfer ownership to the SkDevice's bitmap.
 BitmapPlatformDevice::BitmapPlatformDevice(
     BitmapPlatformDeviceData* data,
     const SkBitmap& bitmap)
     : PlatformDevice(bitmap),
       data_(data) {
   // The data object is already ref'ed for us by create().
+  SkDEBUGCODE(begin_paint_count_ = 0);
 }
 
 // The copy constructor just adds another reference to the underlying data.
 // We use a const cast since the default Skia definitions don't define the
 // proper constedness that we expect (accessBitmap should really be const).
 BitmapPlatformDevice::BitmapPlatformDevice(
     const BitmapPlatformDevice& other)
     : PlatformDevice(
           const_cast<BitmapPlatformDevice&>(other).accessBitmap(true)),
       data_(other.data_) {
   data_->ref();
+  SkDEBUGCODE(begin_paint_count_ = 0);
 }
 
 BitmapPlatformDevice::~BitmapPlatformDevice() {
+  SkASSERT(begin_paint_count_ == 0);
   data_->unref();
 }
 
 BitmapPlatformDevice& BitmapPlatformDevice::operator=(
     const BitmapPlatformDevice& other) {
   data_ = other.data_;
   data_->ref();
   return *this;
 }
 
 HDC BitmapPlatformDevice::BeginPlatformPaint() {
+  SkDEBUGCODE(begin_paint_count_++);
   return data_->GetBitmapDC();
 }
 
+void BitmapPlatformDevice::EndPlatformPaint() {
+  SkASSERT(begin_paint_count_--);
+  PlatformDevice::EndPlatformPaint();
+}
+
 void BitmapPlatformDevice::setMatrixClip(const SkMatrix& transform,
                                          const SkRegion& region,
                                          const SkClipStack&) {
   data_->SetMatrixClip(transform, region);
 }
 
 void BitmapPlatformDevice::drawToHDC(HDC dc, int x, int y,
                                      const RECT* src_rect) {
   bool created_dc = !data_->IsBitmapDCCreated();
   HDC source_dc = BeginPlatformPaint();
@@ skipping 62 matching lines @@
   if (data_->IsBitmapDCCreated())
     GdiFlush();
 }
 
 SkDeviceFactory* BitmapPlatformDevice::onNewDeviceFactory() {
   return SkNEW(BitmapPlatformDeviceFactory);
 }
 
 }  // namespace skia