bug 563864. Add mozPaintCount API. r=smaug,sr=vlad

dom/base/nsGlobalWindow.cpp

@@ -3565,6 +3565,25 @@ nsGlobalWindow::GetMozInnerScreenY(float* aScreenY)
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsGlobalWindow::GetMozPaintCount(PRUint64* aResult)
+{
+  FORWARD_TO_OUTER(GetMozPaintCount, (aResult), NS_ERROR_NOT_INITIALIZED);
+
+  *aResult = 0;
+
+  if (!mDocShell)
+    return NS_OK;
+
+  nsCOMPtr<nsIPresShell> presShell;
+  mDocShell->GetPresShell(getter_AddRefs(presShell));
+  if (!presShell)
+    return NS_OK;
+
+  *aResult = presShell->GetPaintCount();
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsGlobalWindow::SetScreenX(PRInt32 aScreenX)
 {

dom/interfaces/base/nsIDOMWindowInternal.idl

@@ -44,7 +44,7 @@ interface nsIControllers;
 interface nsIDOMLocation;
 interface nsIVariant;
 
-[scriptable, uuid(c2f4433a-8b4c-4676-ab30-3bffd26fb29e)]
+[scriptable, uuid(f18e491b-0c1a-4a9d-9281-32f39fa2d637)]
 interface nsIDOMWindowInternal : nsIDOMWindow2
 {
   readonly attribute nsIDOMWindowInternal        window;
@@ -218,4 +218,10 @@ interface nsIDOMWindowInternal : nsIDOMWindow2
    */
   [binaryname(PostMessageMoz)] void postMessage(in DOMString message,
                                                 in DOMString targetOrigin);
+
+  /**
+   * Returns the number of times this document for this window has
+   * been painted to the screen.
+   */
+  readonly attribute unsigned long long mozPaintCount;
 };

layout/base/nsDisplayList.cpp

@@ -77,7 +77,8 @@ nsDisplayListBuilder::nsDisplayListBuilder(nsIFrame* aReferenceFrame,
       mPaintAllFrames(PR_FALSE),
       mAccurateVisibleRegions(PR_FALSE),
       mInTransform(PR_FALSE),
-      mSyncDecodeImages(PR_FALSE) {
+      mSyncDecodeImages(PR_FALSE),
+      mIsPaintingToWindow(PR_FALSE) {
   PL_InitArenaPool(&mPool, "displayListArena", 1024, sizeof(void*)-1);
 
   nsPresContext* pc = aReferenceFrame->PresContext();
@@ -196,6 +197,10 @@ nsDisplayListBuilder::EnterPresShell(nsIFrame* aReferenceFrame,
 
   state->mPresShell->UpdateCanvasBackground();
 
+  if (mIsPaintingToWindow) {
+    state->mPresShell->IncrementPaintCount();
+  }
+
   if (!mBuildCaret)
     return;
 

layout/base/nsDisplayList.h

@@ -249,6 +249,10 @@ public:
    * so that methods like GetFrameForPoint work when painting is suppressed.
    */
   void IgnorePaintSuppression() { mIsBackgroundOnly = PR_FALSE; }
+  /**
+   * Call this if we're doing normal painting to the window.
+   */
+  void SetPaintingToWindow(PRBool aToWindow) { mIsPaintingToWindow = aToWindow; }
   /**
    * Display the caret if needed.
    */
@@ -424,6 +428,7 @@ private:
   // under an nsDisplayTransform
   PRPackedBool                   mInTransform;
   PRPackedBool                   mSyncDecodeImages;
+  PRPackedBool                   mIsPaintingToWindow;
 };
 
 class nsDisplayItem;

layout/base/nsIPresShell.h

@@ -119,8 +119,8 @@ typedef struct CapturingContentInfo {
 } CapturingContentInfo;
 
 #define NS_IPRESSHELL_IID     \
-{ 0x84f1a428, 0x6bbe, 0x4958, \
-  { 0xa1, 0x08, 0x8a, 0xe0, 0x78, 0xb8, 0x63, 0xf4 } }
+  { 0x47c5b7c4, 0x8d35, 0x4d36, \
+    { 0xa1, 0xf9, 0x19, 0x44, 0xf8, 0xb9, 0x46, 0xb5 } }
 
 // Constants for ScrollContentIntoView() function
 #define NS_PRESSHELL_SCROLL_TOP      0
@@ -984,6 +984,13 @@ public:
     return gCaptureInfo.mPreventDrag && gCaptureInfo.mContent;
   }
 
+  /**
+   * Keep track of how many times this presshell has been rendered to
+   * a window.
+   */
+  PRUint64 GetPaintCount() { return mPaintCount; }
+  void IncrementPaintCount() { ++mPaintCount; }
+
 protected:
   // IMPORTANT: The ownership implicit in the following member variables
   // has been explicitly checked.  If you add any members to this class,
@@ -1004,6 +1011,10 @@ protected:
   nsIFrame*                 mDrawEventTargetFrame;
 #endif
 
+  // Count of the number of times this presshell has been painted to
+  // a window
+  PRUint64                  mPaintCount;
+
   PRInt16                   mSelectionFlags;
 
   PRPackedBool              mStylesHaveChanged;

layout/base/nsLayoutUtils.cpp

@@ -1178,6 +1178,9 @@ nsLayoutUtils::PaintFrame(nsIRenderingContext* aRenderingContext, nsIFrame* aFra
   if (aFlags & PAINT_SYNC_DECODE_IMAGES) {
     builder.SetSyncDecodeImages(PR_TRUE);
   }
+  if (aFlags & PAINT_WIDGET_LAYERS) {
+    builder.SetPaintingToWindow(PR_TRUE);
+  }
   nsresult rv;
 
   builder.EnterPresShell(aFrame, dirtyRect);

layout/base/tests/Makefile.in

@@ -105,6 +105,7 @@ _TEST_FILES =	\
 		test_bug518777.html \
 		test_bug548545.xhtml \
 		test_flush_on_paint.html \
+		test_mozPaintCount.html \
 		test_scroll_selection_into_view.html \
 		test_scrolling.html \
 		$(NULL)

layout/base/tests/test_mozPaintCount.html

@@ -0,0 +1,45 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <title>Tests for mozPaintCount</title>
+  <script type="text/javascript" src="/MochiKit/packed.js"></script>
+  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body onload="doFlicker()">
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+<script class="testbody" type="text/javascript">
+
+SimpleTest.waitForExplicitFinish();
+
+var startPaintCount = window.mozPaintCount;
+var color = 0;
+
+function doFlicker() {
+  if (window.mozPaintCount - startPaintCount > 20) {
+    ok(true, "Got enough paints");
+    SimpleTest.finish();
+    return;
+  }
+
+  color = (color + 1) % 256;
+  document.body.style.backgroundColor = "rgb(" + color + "," + color + "," + color + ")";
+  setTimeout(doFlicker, 0);
+}
+
+</script>
+</pre>
+
+<div style="height:4000px"></div>
+<a id="first"  href="http://www.mozilla.org/">first<br>link</a>
+<a id="second" href="http://www.mozilla.org/">second link</a>
+<a id="third"  href="http://www.mozilla.org/">third<br>link</a>
+<div style="height:4000px"></div>
+
+</body>
+</html>
+