Bug 844819 - Don't create DrawTargets for invalid cairo surfaces. r=Bas

gfx/thebes/gfxContext.cpp

@@ -575,6 +575,10 @@ gfxContext::DrawSurface(gfxASurface *surface, const gfxSize& size)
     RefPtr<SourceSurface> surf =
       gfxPlatform::GetPlatform()->GetSourceSurfaceForSurface(mDT, surface);
 
+    if (!surf) {
+      return;
+    }
+
     Rect rect(0, 0, Float(size.width), Float(size.height));
     rect.Intersect(Rect(0, 0, Float(surf->GetSize().width), Float(surf->GetSize().height)));
 
@@ -1389,6 +1393,7 @@ gfxContext::SetSource(gfxASurface *surface, const gfxPoint& offset)
     CurrentState().sourceSurfCairo = surface;
     CurrentState().sourceSurface =
       gfxPlatform::GetPlatform()->GetSourceSurfaceForSurface(mDT, surface);
+    CurrentState().color = Color(0, 0, 0, 0);
   }
 }
 
@@ -1492,6 +1497,10 @@ gfxContext::Mask(gfxASurface *surface, const gfxPoint& offset)
     RefPtr<SourceSurface> sourceSurf =
       gfxPlatform::GetPlatform()->GetSourceSurfaceForSurface(mDT, surface);
 
+    if (!sourceSurf) {
+      return;
+    }
+
     gfxPoint pt = surface->GetDeviceOffset();
 
     // We clip here to bind to the mask surface bounds, see above.

gfx/thebes/gfxPlatform.cpp

@@ -641,6 +641,10 @@ gfxPlatform::ClearSourceSurfaceForSurface(gfxASurface *aSurface)
 RefPtr<SourceSurface>
 gfxPlatform::GetSourceSurfaceForSurface(DrawTarget *aTarget, gfxASurface *aSurface)
 {
+  if (!aSurface->CairoSurface() || aSurface->CairoStatus()) {
+    return nullptr;
+  }
+
   void *userData = aSurface->GetData(&kSourceSurface);
 
   if (userData) {
@@ -737,10 +741,6 @@ gfxPlatform::GetSourceSurfaceForSurface(DrawTarget *aTarget, gfxASurface *aSurfa
       // alive. This is true if gfxASurface actually -is- an ImageSurface or
       // if it is a gfxWindowsSurface which supports GetAsImageSurface.
       if (imgSurface != aSurface && !isWin32ImageSurf) {
-        // This shouldn't happen for now, it can be easily supported by making
-        // a copy. For now let's just abort.
-        NS_RUNTIMEABORT("Attempt to create unsupported SourceSurface from"
-            "non-image surface.");
         return nullptr;
       }