initialize the Rendering Context from a GrafPort to fix a crash on print

gfx/src/mac/nsDeviceContextMac.cpp

@@ -80,7 +80,7 @@ double				pix_inch;
  */
 NS_IMETHODIMP nsDeviceContextMac :: CreateRenderingContext(nsIRenderingContext *&aContext)
 {
-nsIRenderingContext   *pContext;
+nsRenderingContextMac *pContext;
 nsresult              rv;
 GrafPtr								thePort;
 

gfx/src/mac/nsRenderingContextMac.cpp

@@ -464,6 +464,24 @@ NS_IMETHODIMP nsRenderingContextMac::Init(nsIDeviceContext* aContext, nsDrawingS
 
 //------------------------------------------------------------------------
 
+// used by nsDeviceContextMac::CreateRenderingContext() for printing
+nsresult nsRenderingContextMac::Init(nsIDeviceContext* aContext, GrafPtr aPort)
+{
+  mContext = aContext;
+  NS_IF_ADDREF(mContext);
+ 
+	if (mOriginalSurface->GetPort() == nsnull)
+		mOriginalSurface->Init(aPort);
+
+ 	// select the surface
+	mFrontSurface->Init(aPort);
+	SelectDrawingSurface(mFrontSurface);
+
+  return NS_OK;
+}
+
+//------------------------------------------------------------------------
+
 void	nsRenderingContextMac::SelectDrawingSurface(DrawingSurface* aSurface)
 {
 	if (! aSurface)

gfx/src/mac/nsRenderingContextMac.h

@@ -111,6 +111,7 @@ public:
   //locals
   NS_IMETHOD SetClipRectInPixels(const nsRect& aRect, nsClipCombine aCombine, PRBool &aClipEmpty);
   NS_IMETHOD SetPortTextState();
+  nsresult   Init(nsIDeviceContext* aContext, GrafPtr aPort);
 
 protected:
 	void		SelectDrawingSurface(DrawingSurface* aSurface);

widget/src/mac/nsDeviceContextMac.cpp

@@ -80,7 +80,7 @@ double				pix_inch;
  */
 NS_IMETHODIMP nsDeviceContextMac :: CreateRenderingContext(nsIRenderingContext *&aContext)
 {
-nsIRenderingContext   *pContext;
+nsRenderingContextMac *pContext;
 nsresult              rv;
 GrafPtr								thePort;