Optionally clear PlatformCanvas instances.

skia/ext/vector_platform_device_skia.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 "skia/ext/vector_platform_device_skia.h"
 
 #include "skia/ext/bitmap_platform_device.h"
 #include "third_party/skia/include/core/SkClipStack.h"
 #include "third_party/skia/include/core/SkDraw.h"
 #include "third_party/skia/include/core/SkRect.h"
@@ skipping 23 matching lines @@
   return false;
 }
 
 PlatformSurface VectorPlatformDeviceSkia::BeginPlatformPaint() {
   // Even when drawing a vector representation of the page, we have to
   // provide a raster surface for plugins to render into - they don't have
   // a vector interface.  Therefore we create a BitmapPlatformDevice here
   // and return the context from it, then layer on the raster data as an
   // image in EndPlatformPaint.
   DCHECK(raster_surface_ == NULL);
-#if defined(OS_WIN)
-  raster_surface_ = BitmapPlatformDevice::create(width(),
-                                                 height(),
-                                                 false, /* not opaque */
-                                                 NULL);
-#elif defined(OS_POSIX) && !defined(OS_MACOSX)
-  raster_surface_ = BitmapPlatformDevice::Create(width(),
-                                                 height(),
-                                                 false /* not opaque */);
-#endif
+  raster_surface_ = BitmapPlatformDevice::CreateAndClear(width(), height(),
+                                                         false);
   raster_surface_->unref();  // SkRefPtr and create both took a reference.
-
-  SkCanvas canvas(raster_surface_.get());
   return raster_surface_->BeginPlatformPaint();
 }
 
 void VectorPlatformDeviceSkia::EndPlatformPaint() {
   DCHECK(raster_surface_ != NULL);
   SkPaint paint;
   // SkPDFDevice checks the passed SkDraw for an empty clip (only).  Fake
   // it out by setting a non-empty clip.
   SkDraw draw;
   SkRegion clip(SkIRect::MakeWH(width(), height()));
@@ skipping 23 matching lines @@
 }
 #elif defined(OS_LINUX) || defined(OS_ANDROID) || defined(OS_OPENBSD)
 void VectorPlatformDeviceSkia::DrawToNativeContext(
     PlatformSurface surface, int x, int y, const PlatformRect* src_rect) {
   // Should never be called on Linux.
   SkASSERT(false);
 }
 #endif
 
 }  // namespace skia