Bug 253889 - part 1: Get rid of nsIPresShell from gfx r=jwatt

`gfxUtils::WriteAsPNG()` is the only user of `nsIPresShell` in `gfx`, but
nobody calls it.  So, we can get rid of it with `nsIPresShell` reference.

Differential Revision: https://phabricator.services.mozilla.com/D29310

--HG--
extra : moz-landing-system : lando

gfx/thebes/gfxSVGGlyphs.h

@@ -17,10 +17,10 @@
 #include "nsRefreshDriver.h"
 
 class nsIContentViewer;
-class nsIPresShell;
 class gfxSVGGlyphs;
 
 namespace mozilla {
+class PresShell;
 class SVGContextPaint;
 namespace dom {
 class Document;

gfx/thebes/gfxUtils.cpp

@@ -38,7 +38,6 @@
 #include "nsIClipboardHelper.h"
 #include "nsIFile.h"
 #include "nsIGfxInfo.h"
-#include "nsIPresShell.h"
 #include "nsMimeTypes.h"
 #include "nsPresContext.h"
 #include "nsRegion.h"
@@ -1228,24 +1227,6 @@ void gfxUtils::WriteAsPNG(DrawTarget* aDT, const char* aFile) {
   }
 }
 
-/* static */
-void gfxUtils::WriteAsPNG(nsIPresShell* aShell, const char* aFile) {
-  int32_t width = 1000, height = 1000;
-  nsRect r(0, 0, aShell->GetPresContext()->DevPixelsToAppUnits(width),
-           aShell->GetPresContext()->DevPixelsToAppUnits(height));
-
-  RefPtr<mozilla::gfx::DrawTarget> dt =
-      gfxPlatform::GetPlatform()->CreateOffscreenContentDrawTarget(
-          IntSize(width, height), SurfaceFormat::B8G8R8A8);
-  NS_ENSURE_TRUE(dt && dt->IsValid(), /*void*/);
-
-  RefPtr<gfxContext> context = gfxContext::CreateOrNull(dt);
-  MOZ_ASSERT(context);  // already checked the draw target above
-  aShell->RenderDocument(r, RenderDocumentFlags::None, NS_RGB(255, 255, 0),
-                         context);
-  WriteAsPNG(dt.get(), aFile);
-}
-
 /* static */
 void gfxUtils::DumpAsDataURI(SourceSurface* aSurface, FILE* aFile) {
   EncodeSourceSurface(aSurface, ImageType::PNG, EmptyString(), eDataURIEncode,

gfx/thebes/gfxUtils.h

@@ -24,7 +24,6 @@ class gfxDrawable;
 struct gfxQuad;
 class nsIInputStream;
 class nsIGfxInfo;
-class nsIPresShell;
 
 namespace mozilla {
 namespace dom {
@@ -267,7 +266,6 @@ class gfxUtils {
   static void WriteAsPNG(SourceSurface* aSurface, const char* aFile);
   static void WriteAsPNG(DrawTarget* aDT, const nsAString& aFile);
   static void WriteAsPNG(DrawTarget* aDT, const char* aFile);
-  static void WriteAsPNG(nsIPresShell* aShell, const char* aFile);
 
   /**
    * Dump as a PNG encoded Data URL to a FILE stream (using stdout by