Closures for swap promises must be cross-thread.

Upon landing of <http://crrev.com/c/765749>, which tightened up the threading
check of WTF::Function, a few assertion failures were reported.

The stack traces indicated closures for swap promises (in PaintTiming.cpp
and FirstMeaningfulPaintDetector.cpp) might end up getting destructed on the
compositor thread. To allow this, WTF::CrossThreadBind() must be used instead
of WTF::Bind().

Bug: 786194
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
Change-Id: I9252eff15ca00e1bc0dfc8f87629ccb9acb56714
Reviewed-on: https://chromium-review.googlesource.com/776343Reviewed-by: Taiju Tsuiki <tzik@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: enne <enne@chromium.org>
Commit-Queue: enne <enne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#517471}

third_party/WebKit/Source/core/paint/FirstMeaningfulPaintDetector.cpp

@@ -7,10 +7,10 @@
 #include "core/css/FontFaceSetDocument.h"
 #include "core/paint/PaintTiming.h"
 #include "core/probe/CoreProbes.h"
+#include "platform/CrossThreadFunctional.h"
 #include "platform/Histogram.h"
 #include "platform/instrumentation/tracing/TraceEvent.h"
 #include "platform/loader/fetch/ResourceFetcher.h"
-#include "platform/wtf/Functional.h"
 #include "public/platform/TaskType.h"
 #include "public/platform/WebLayerTreeView.h"
 
@@ -247,8 +247,8 @@ void FirstMeaningfulPaintDetector::ReportHistograms() {
 void FirstMeaningfulPaintDetector::RegisterNotifySwapTime(PaintEvent event) {
   ++outstanding_swap_promise_count_;
   paint_timing_->RegisterNotifySwapTime(
-      event, WTF::Bind(&FirstMeaningfulPaintDetector::ReportSwapTime,
-                       WrapCrossThreadWeakPersistent(this), event));
+      event, CrossThreadBind(&FirstMeaningfulPaintDetector::ReportSwapTime,
+                             WrapCrossThreadWeakPersistent(this), event));
 }
 
 void FirstMeaningfulPaintDetector::ReportSwapTime(

third_party/WebKit/Source/core/paint/PaintTiming.cpp

@@ -19,6 +19,7 @@
 #include "core/probe/CoreProbes.h"
 #include "core/timing/DOMWindowPerformance.h"
 #include "core/timing/Performance.h"
+#include "platform/CrossThreadFunctional.h"
 #include "platform/Histogram.h"
 #include "platform/WebFrameScheduler.h"
 #include "platform/instrumentation/tracing/TraceEvent.h"
@@ -185,9 +186,9 @@ void PaintTiming::SetFirstContentfulPaint(double stamp) {
 }
 
 void PaintTiming::RegisterNotifySwapTime(PaintEvent event) {
-  RegisterNotifySwapTime(event,
-                         WTF::Bind(&PaintTiming::ReportSwapTime,
-                                   WrapCrossThreadWeakPersistent(this), event));
+  RegisterNotifySwapTime(
+      event, CrossThreadBind(&PaintTiming::ReportSwapTime,
+                             WrapCrossThreadWeakPersistent(this), event));
 }
 
 void PaintTiming::RegisterNotifySwapTime(PaintEvent event,

third_party/WebKit/Source/core/paint/PaintTiming.h

@@ -29,7 +29,7 @@ class CORE_EXPORT PaintTiming final
   USING_GARBAGE_COLLECTED_MIXIN(PaintTiming);
   friend class FirstMeaningfulPaintDetector;
   using ReportTimeCallback =
-      WTF::Function<void(WebLayerTreeView::SwapResult, double)>;
+      WTF::CrossThreadFunction<void(WebLayerTreeView::SwapResult, double)>;
 
  public:
   virtual ~PaintTiming() {}