Move uncoupled code out of skia/ext/platform_device.h

skia/ext/platform_canvas.h

Index: skia/ext/platform_canvas.h
diff --git a/skia/ext/platform_canvas.h b/skia/ext/platform_canvas.h
index c46d6c4cc0cec94356a0e419df5fe70e2021dc15..408dddadbf582eb450115e83566488ccafc8f5f5 100644
--- a/skia/ext/platform_canvas.h
+++ b/skia/ext/platform_canvas.h
@@ -8,13 +8,15 @@
 // The platform-specific device will include the necessary platform headers
 // to get the surface type.
 #include "base/basictypes.h"
-#include "skia/ext/platform_device.h"
+#include "skia/ext/platform_surface.h"
 #include "skia/ext/refptr.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkPixelRef.h"
 #include "third_party/skia/include/core/SkPixmap.h"
 
+class SkBaseDevice;
+
 namespace skia {
 
 typedef SkCanvas PlatformCanvas;
@@ -171,6 +173,21 @@ class SK_API ScopedPlatformPaint {
   ScopedPlatformPaint& operator=(const ScopedPlatformPaint&);
 };
 
+// Following routines are used in print preview workflow to mark the
+// preview metafile.
+SK_API SkMetaData& getMetaData(const SkCanvas& canvas);

[f(malita), 2015/11/24 23:13:23]

Nit: GetMetaData(...)?

[f(malita), 2015/11/24 23:13:23]

Also, I don't think we have any external users for this.  Can we relocate it to
anonymous namespace, in platform_canvas.cc?

[Tom Hudson, 2015/11/25 15:50:35]

Done.

[Tom Hudson, 2015/11/25 15:50:35]

Done.

[Tom Hudson, 2015/11/25 15:50:35]

printing/metafile_skia_wrapper.cc uses it twice, and GraphicsContext and
WebLocalFrameImpl from Blink as well. GraphicsContext is the only one I can
easily see wrapping; perhaps the WebLocalFrameImpl, but the Metafile is too
weird to be a straightforward refactoring.



In Blink, we see WebLocalFrameImpl storing the metadata on a GraphicsContext in
spoolSinglePage() and spoolAllPagesWithBoundaries(), and
GraphicsContext::beginRecording() setting the metadata on the (device backing
the) canvas it spawns.)

WebLocalFrameImpl is entered from PrintWebViewHelper; the linux implementation,
at least, is explicitly using MetafileSkiaWrapper to track the metafile in the
Canvas' metadata.

So it all ties together: as long as we have to track the metafile, it gets
tunnelled through WebLocalFrameImpl, GraphicsContext, and SkPictureBuilder so
that the canvases created for print results all know about the metafile
specified at the start of the printing process.

+
+#if defined(OS_MACOSX)
+SK_API void SetIsPreviewMetafile(const SkCanvas& canvas, bool is_preview);
+SK_API bool IsPreviewMetafile(const SkCanvas& canvas);
+#endif
+
+#if defined(OS_MACOSX)

[f(malita), 2015/11/24 23:13:23]

Nit: consolidate ifdefs

[Tom Hudson, 2015/11/25 15:50:35]

Done.

Odd that we also have some things under __APPLE__ guards in the same file, but
I'm going to guess that those are both OSX *and* iOS, and these aren't (yet?).

+// Returns the CGContext that backing the SkCanvas.
+// Returns NULL if none is bound.
+SK_API CGContextRef GetBitmapContext(const SkCanvas& canvas);
+#endif
+
 }  // namespace skia
 
 #endif  // SKIA_EXT_PLATFORM_CANVAS_H_