Bug 586954 - Set a proper clip region so that PushGroup doesn't allocate a giant surface. This speeds up drawing of masked non-SVG elements. r+a=roc

layout/svg/base/src/nsSVGIntegrationUtils.cpp

@@ -290,6 +290,8 @@ nsSVGIntegrationUtils::PaintFramesWithEffects(nsIRenderingContext* aCtx,
   if (opacity != 1.0f || maskFrame || (clipPathFrame && !isTrivialClip)) {
     complexEffects = PR_TRUE;
     gfx->Save();
+    aCtx->SetClipRect(aEffectsFrame->GetVisualOverflowRect(),
+                      nsClipCombine_kIntersect);
     gfx->PushGroup(gfxASurface::CONTENT_COLOR_ALPHA);
   }