Bug 847890 - paint flashing for content only. r=roc

dom/base/nsDOMWindowUtils.cpp

@@ -3210,6 +3210,35 @@ nsDOMWindowUtils::IsNodeDisabledForEvents(nsIDOMNode* aNode, bool* aRetVal)
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsDOMWindowUtils::SetPaintFlashing(bool aPaintFlashing)
+{
+  nsPresContext* presContext = GetPresContext();
+  if (presContext) {
+    presContext->RefreshDriver()->SetPaintFlashing(aPaintFlashing);
+    // Clear paint flashing colors
+    nsIPresShell* presShell = GetPresShell();
+    if (!aPaintFlashing && presShell) {
+      nsIFrame* rootFrame = presShell->GetRootFrame();
+      if (rootFrame) {
+        rootFrame->InvalidateFrameSubtree();
+      }
+    }
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDOMWindowUtils::GetPaintFlashing(bool* aRetVal)
+{
+  *aRetVal = false;
+  nsPresContext* presContext = GetPresContext();
+  if (presContext) {
+    *aRetVal = presContext->RefreshDriver()->GetPaintFlashing();
+  }
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsDOMWindowUtils::DispatchEventToChromeOnly(nsIDOMEventTarget* aTarget,
                                             nsIDOMEvent* aEvent,

dom/interfaces/base/nsIDOMWindowUtils.idl

@@ -1349,4 +1349,9 @@ interface nsIDOMWindowUtils : nsISupports {
     * attribute or -moz-user-input: none/disabled.
     */
    boolean isNodeDisabledForEvents(in nsIDOMNode aNode);
+
+   /**
+    * Setting paintFlashing to true will flash newly painted area.
+    */
+   attribute boolean paintFlashing;
 };

layout/base/FrameLayerBuilder.cpp

@@ -759,22 +759,11 @@ FrameLayerBuilder::Init(nsDisplayListBuilder* aBuilder, LayerManager* aManager)
 void
 FrameLayerBuilder::FlashPaint(gfxContext *aContext)
 {
-  static bool sPaintFlashingEnabled;
-  static bool sPaintFlashingPrefCached = false;
-
-  if (!sPaintFlashingPrefCached) {
-    sPaintFlashingPrefCached = true;
-    mozilla::Preferences::AddBoolVarCache(&sPaintFlashingEnabled,
-                                          "nglayout.debug.paint_flashing");
-  }
-
-  if (sPaintFlashingEnabled) {
-    float r = float(rand()) / RAND_MAX;
-    float g = float(rand()) / RAND_MAX;
-    float b = float(rand()) / RAND_MAX;
-    aContext->SetColor(gfxRGBA(r, g, b, 0.2));
-    aContext->Paint();
-  }
+  float r = float(rand()) / RAND_MAX;
+  float g = float(rand()) / RAND_MAX;
+  float b = float(rand()) / RAND_MAX;
+  aContext->SetColor(gfxRGBA(r, g, b, 0.4));
+  aContext->Paint();
 }
 
 FrameLayerBuilder::DisplayItemData*
@@ -3361,7 +3350,10 @@ FrameLayerBuilder::DrawThebesLayer(ThebesLayer* aLayer,
     aContext->Restore();
   }
 
-  FlashPaint(aContext);
+  if (presContext->RefreshDriver()->GetPaintFlashing()) {
+    FlashPaint(aContext);
+  }
+
   if (!aRegionToInvalidate.IsEmpty()) {
     aLayer->AddInvalidRect(aRegionToInvalidate.GetBounds());
   }

layout/base/nsRefreshDriver.cpp

@@ -528,6 +528,8 @@ nsRefreshDriver::nsRefreshDriver(nsPresContext* aPresContext)
   mMostRecentRefreshEpochTime = JS_Now();
   mMostRecentRefresh = TimeStamp::Now();
 
+  mPaintFlashing = Preferences::GetBool("nglayout.debug.paint_flashing");
+
   mRequests.Init();
 }
 

layout/base/nsRefreshDriver.h

@@ -229,6 +229,17 @@ public:
    */
   static int32_t DefaultInterval();
 
+  /**
+   * Enable/disable paint flashing.
+   */
+  void SetPaintFlashing(bool aPaintFlashing) {
+    mPaintFlashing = aPaintFlashing;
+  }
+
+  bool GetPaintFlashing() {
+    return mPaintFlashing;
+  }
+
 private:
   typedef nsTObserverArray<nsARefreshObserver*> ObserverArray;
   typedef nsTHashtable<nsISupportsHashKey> RequestTable;
@@ -265,6 +276,7 @@ private:
   bool mTestControllingRefreshes;
   bool mViewManagerFlushIsPending;
   bool mRequestedHighPrecision;
+  bool mPaintFlashing;
 
   int64_t mMostRecentRefreshEpochTime;
   mozilla::TimeStamp mMostRecentRefresh;

layout/base/tests/chrome/Makefile.in

@@ -51,6 +51,7 @@ MOCHITEST_CHROME_FILES = \
 	test_passpointerevents.html \
 	     passpointerevents_window.html \
 	test_bug812817.xul \
+	test_bug847890_paintFlashing.html \
 	$(NULL)
 
 ifdef MOZ_DEBUG

layout/base/tests/chrome/test_bug847890_paintFlashing.html

@@ -0,0 +1,31 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <title>Tests for paint flashing</title>
+  <script type="text/javascript" src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"/>
+  <script type="text/javascript" src="chrome://mochikit/content/tests/SimpleTest/WindowSnapshot.js"></script>
+  <script type="text/javascript" src="chrome://mochikit/content/tests/SimpleTest/paint_listener.js"></script>
+
+  <script type="application/javascript">
+    SimpleTest.waitForExplicitFinish();
+    function startTest() {
+      waitForAllPaintsFlushed(function () {
+        var before = snapshotWindow(window, false);
+        SpecialPowers.getDOMWindowUtils(window).paintFlashing = true;
+        document.body.innerHTML = "bar";
+        waitForAllPaintsFlushed(function () {
+          document.body.innerHTML = "foo";
+          waitForAllPaintsFlushed(function () {
+            var after = snapshotWindow(window, false);
+            ok(compareSnapshots(before, after, false)[0], "windows are different");
+            SpecialPowers.getDOMWindowUtils(window).paintFlashing = false;
+            SimpleTest.finish();
+          });
+        });
+      });
+    }
+  </script>
+</head>
+<body onload="startTest()">foo</body>
+</html>