import changes from `dev' branch of rmottola/Arctic-Fox:

- Bug 1177013 - Don't allow prio messages while dispatching sync messages (r=dvander) (33130e842)
- Bug 1177013 - Add-on install test changes (r=mrbkap) (adc25d1d7)
- Bug 1177013 - Modernize test_cpows.xul (r=dvander) (77d7a5230)
- Bug 1142109 - Process incoming urgent messages before sending (r=dvander) (261ab15a7)
- Bug 1177013 - CancelCurrentTransaction IPC support (r=dvander) (ef63723f8)
- Bug 1177013 - Fix big IPC comment (r=dvander) (3628041b4)
- Bug 1144745 - Scale GTK widgets properly on HiDPI r=karlt (7923df05d)
- Bug 1127752 - fixes for using Skia and OMTC with GTK3. r=jrmuizel (1e22d442d)
- Bug 1165515 - Part 2: Add MOZ_LOG_TEST. r=froydnj (4a5a1e4be)
- Bug 1171833 - Remove PL_DHashTableEnumerator use from nsPropertyTable. r=smaug. (7bcb19947)

gfx/layers/basic/BasicCompositor.cpp

@@ -522,7 +522,7 @@ BasicCompositor::BeginFrame(const nsIntRegion& aInvalidRegion,
   RefPtr<CompositingRenderTarget> target = CreateRenderTarget(mInvalidRect, INIT_MODE_CLEAR);
   if (!target) {
     if (!mTarget) {
-      mWidget->EndRemoteDrawing();
+      mWidget->EndRemoteDrawingInRegion(mDrawTarget, mInvalidRegion);
     }
     return;
   }
@@ -584,7 +584,7 @@ BasicCompositor::EndFrame()
                       IntPoint(r->x - offset.x, r->y - offset.y));
   }
   if (!mTarget) {
-    mWidget->EndRemoteDrawing();
+    mWidget->EndRemoteDrawingInRegion(mDrawTarget, mInvalidRegion);
   }
 
   mDrawTarget = nullptr;