Bug 590294, part 4: IGNORE_VIEWPORT_SCROLLING currently implies interpreting the visible region as being relative to document space. Displayport rendering wants everything IGNORE_VIEWPORT_SCROLLING implies, except it wants the visible region to be relative to the viewport. So, split the coordinate-space interpretation into a new flag DOCUMENT_RELATIVE, which interprets the visible region as document-relative. r=tn sr=roc

content/canvas/src/nsCanvasRenderingContext2D.cpp

@@ -3730,12 +3730,14 @@ nsCanvasRenderingContext2D::DrawWindow(nsIDOMWindow* aWindow, float aX, float aY
              nsPresContext::CSSPixelsToAppUnits(aY),
              nsPresContext::CSSPixelsToAppUnits(aW),
              nsPresContext::CSSPixelsToAppUnits(aH));
-    PRUint32 renderDocFlags = nsIPresShell::RENDER_IGNORE_VIEWPORT_SCROLLING;
+    PRUint32 renderDocFlags = (nsIPresShell::RENDER_IGNORE_VIEWPORT_SCROLLING |
+                               nsIPresShell::RENDER_DOCUMENT_RELATIVE);
     if (flags & nsIDOMCanvasRenderingContext2D::DRAWWINDOW_DRAW_CARET) {
         renderDocFlags |= nsIPresShell::RENDER_CARET;
     }
     if (flags & nsIDOMCanvasRenderingContext2D::DRAWWINDOW_DRAW_VIEW) {
-        renderDocFlags &= ~nsIPresShell::RENDER_IGNORE_VIEWPORT_SCROLLING;
+        renderDocFlags &= ~(nsIPresShell::RENDER_IGNORE_VIEWPORT_SCROLLING |
+                            nsIPresShell::RENDER_DOCUMENT_RELATIVE);
     }
     if (flags & nsIDOMCanvasRenderingContext2D::DRAWWINDOW_USE_WIDGET_LAYERS) {
         renderDocFlags |= nsIPresShell::RENDER_USE_WIDGET_LAYERS;

layout/base/nsIPresShell.h

@@ -841,6 +841,8 @@ public:
    *   set RENDER_ASYNC_DECODE_IMAGES to avoid having images synchronously
    * decoded during rendering.
    * (by default images decode synchronously with RenderDocument)
+   *   set RENDER_DOCUMENT_RELATIVE to interpret |aRect| relative to the
+   * document instead of the CSS viewport
    * @param aBackgroundColor a background color to render onto
    * @param aRenderedContext the gfxContext to render to. We render so that
    * one CSS pixel in the source document is rendered to one unit in the current
@@ -851,7 +853,8 @@ public:
     RENDER_IGNORE_VIEWPORT_SCROLLING = 0x02,
     RENDER_CARET = 0x04,
     RENDER_USE_WIDGET_LAYERS = 0x08,
-    RENDER_ASYNC_DECODE_IMAGES = 0x10
+    RENDER_ASYNC_DECODE_IMAGES = 0x10,
+    RENDER_DOCUMENT_RELATIVE = 0x20
   };
   virtual NS_HIDDEN_(nsresult) RenderDocument(const nsRect& aRect, PRUint32 aFlags,
                                               nscolor aBackgroundColor,

layout/base/nsLayoutUtils.cpp

@@ -1267,11 +1267,13 @@ nsLayoutUtils::PaintFrame(nsIRenderingContext* aRenderingContext, nsIFrame* aFra
     if (rootScrollFrame) {
       nsIScrollableFrame* rootScrollableFrame =
         presShell->GetRootScrollFrameAsScrollable();
-      // Make visibleRegion and aRenderingContext relative to the
-      // scrolled frame instead of the root frame.
-      nsPoint pos = rootScrollableFrame->GetScrollPosition();
-      visibleRegion.MoveBy(-pos);
-      aRenderingContext->Translate(pos.x, pos.y);
+      if (aFlags & PAINT_DOCUMENT_RELATIVE) {
+        // Make visibleRegion and aRenderingContext relative to the
+        // scrolled frame instead of the root frame.
+        nsPoint pos = rootScrollableFrame->GetScrollPosition();
+        visibleRegion.MoveBy(-pos);
+        aRenderingContext->Translate(pos.x, pos.y);
+      }
       builder.SetIgnoreScrollFrame(rootScrollFrame);
 
       nsCanvasFrame* canvasFrame =
@@ -1402,7 +1404,7 @@ nsLayoutUtils::PaintFrame(nsIRenderingContext* aRenderingContext, nsIFrame* aFra
       // paint in a window, so make sure we flush out any retained layer
       // trees before *and after* we draw
       flags |= nsDisplayList::PAINT_FLUSH_LAYERS;
-    } else if (widget) {
+    } else if (widget && !(aFlags & PAINT_DOCUMENT_RELATIVE)) {
       // XXX we should simplify this API now that dirtyWindowRegion always
       // covers the entire window
       widget->UpdatePossiblyTransparentRegion(dirtyWindowRegion, visibleWindowRegion);

layout/base/nsLayoutUtils.h

@@ -517,9 +517,10 @@ public:
     PAINT_SYNC_DECODE_IMAGES = 0x02,
     PAINT_WIDGET_LAYERS = 0x04,
     PAINT_IGNORE_SUPPRESSION = 0x08,
-    PAINT_IGNORE_VIEWPORT_SCROLLING = 0x10,
+    PAINT_DOCUMENT_RELATIVE = 0x10,
     PAINT_HIDE_CARET = 0x20,
-    PAINT_ALL_CONTINUATIONS = 0x40
+    PAINT_ALL_CONTINUATIONS = 0x40,
+    PAINT_IGNORE_VIEWPORT_SCROLLING = 0x80
   };
 
   /**
@@ -543,6 +544,9 @@ public:
    * even if aRenderingContext is non-null. This is useful if you want
    * to force rendering to use the widget's layer manager for testing
    * or speed. PAINT_WIDGET_LAYERS must be set if aRenderingContext is null.
+   * If PAINT_DOCUMENT_RELATIVE is used, the visible region is interpreted
+   * as being relative to the document.  (Normally it's relative to the CSS
+   * viewport.)
    *
    * So there are three possible behaviours:
    * 1) PAINT_WIDGET_LAYERS is set and aRenderingContext is null; we paint

layout/base/nsPresShell.cpp

@@ -5294,6 +5294,9 @@ PresShell::RenderDocument(const nsRect& aRect, PRUint32 aFlags,
   if (aFlags & RENDER_IGNORE_VIEWPORT_SCROLLING) {
     flags |= nsLayoutUtils::PAINT_IGNORE_VIEWPORT_SCROLLING;
   }
+  if (aFlags & RENDER_DOCUMENT_RELATIVE) {
+    flags |= nsLayoutUtils::PAINT_DOCUMENT_RELATIVE;
+  }
   nsLayoutUtils::PaintFrame(rc, rootFrame, nsRegion(aRect),
                             aBackgroundColor, flags);