Bug 1059033 - Part 6: Clip text drawing to its bound so we can skip unaffected tiles. r=Bas

--HG--
extra : rebase_source : 60d0462767f625d91261b40b930ee165f0126173

layout/generic/nsTextFrame.cpp

@@ -4570,8 +4570,20 @@ nsDisplayText::Paint(nsDisplayListBuilder* aBuilder,
   extraVisible.Inflate(appUnitsPerDevPixel, appUnitsPerDevPixel);
   nsTextFrame* f = static_cast<nsTextFrame*>(mFrame);
 
-  gfxContextAutoDisableSubpixelAntialiasing disable(aCtx->ThebesContext(),
+  gfxContext* ctx = aCtx->ThebesContext();
+  gfxContextAutoDisableSubpixelAntialiasing disable(ctx,
                                                     mDisableSubpixelAA);
+  gfxContextAutoSaveRestore save(ctx);
+
+  gfxRect pixelVisible =
+    nsLayoutUtils::RectToGfxRect(extraVisible, appUnitsPerDevPixel);
+  pixelVisible.Inflate(2);
+  pixelVisible.RoundOut();
+
+  ctx->NewPath();
+  ctx->Rectangle(pixelVisible);
+  ctx->Clip();
+
   NS_ASSERTION(mLeftEdge >= 0, "illegal left edge");
   NS_ASSERTION(mRightEdge >= 0, "illegal right edge");
   f->PaintText(aCtx, ToReferenceFrame(), extraVisible, *this);

layout/reftests/scrolling/reftest.list

@@ -1,6 +1,6 @@
 skip-if(B2G&&browserIsRemote) HTTP == deferred-anchor.xhtml#d deferred-anchor-ref.xhtml#d
 == deferred-anchor2.xhtml deferred-anchor-ref.xhtml#d
-HTTP == fixed-1.html fixed-1.html?ref
+ffuzzy-if(/^Windows\x20NT\x206\.2/.test(http.oscpu),1,4) HTTP == fixed-1.html fixed-1.html?ref
 HTTP == fixed-opacity-1.html fixed-opacity-1.html?ref
 skip-if(B2G) HTTP == fixed-opacity-2.html fixed-opacity-2.html?ref
 skip-if(B2G) random-if(gtk2Widget) fuzzy-if(Android,3,60) HTTP == fixed-text-1.html fixed-text-1.html?ref