From 50f59c86bf6019f9d8f0f0c12a9009856bbbef05 Mon Sep 17 00:00:00 2001
From: Robert O'Callahan <robert@ocallahan.org>
Date: Mon, 8 Nov 2010 22:06:14 +1300
Subject: [PATCH] Bug 598470. Treat all chrome display items as opaque when
 we're computing plugin visibility regions; this ensures translucent chrome
 content is visible above windowed plugins. r=tnikkel,a=blocker

---
 layout/base/nsDisplayList.cpp                 | 24 +++++--
 layout/base/nsDisplayList.h                   | 18 ++++--
 layout/base/nsLayoutUtils.cpp                 |  6 +-
 layout/base/nsPresContext.cpp                 |  3 +-
 layout/base/nsPresShell.cpp                   |  2 +-
 layout/base/tests/chrome/Makefile.in          |  2 +
 .../chrome/chrome_over_plugin_window.xul      | 62 +++++++++++++++++++
 .../tests/chrome/test_chrome_over_plugin.xul  | 25 ++++++++
 layout/generic/nsGfxScrollFrame.cpp           |  2 +-
 layout/generic/nsObjectFrame.cpp              | 16 +++++
 xpcom/glue/nsTArray.h                         |  6 ++
 11 files changed, 153 insertions(+), 13 deletions(-)
 create mode 100644 layout/base/tests/chrome/chrome_over_plugin_window.xul
 create mode 100644 layout/base/tests/chrome/test_chrome_over_plugin.xul

diff --git a/layout/base/nsDisplayList.cpp b/layout/base/nsDisplayList.cpp
index 003acafe998..31147b70cdf 100644
--- a/layout/base/nsDisplayList.cpp
+++ b/layout/base/nsDisplayList.cpp
@@ -68,12 +68,12 @@ using namespace mozilla;
 using namespace mozilla::layers;
 
 nsDisplayListBuilder::nsDisplayListBuilder(nsIFrame* aReferenceFrame,
-    PRBool aIsForEvents, PRBool aBuildCaret)
+    Mode aMode, PRBool aBuildCaret)
     : mReferenceFrame(aReferenceFrame),
       mIgnoreScrollFrame(nsnull),
       mCurrentTableItem(nsnull),
       mBuildCaret(aBuildCaret),
-      mEventDelivery(aIsForEvents),
+      mMode(aMode),
       mIgnoreSuppression(PR_FALSE),
       mHadToIgnoreSuppression(PR_FALSE),
       mIsAtRootOfPseudoStackingContext(PR_FALSE),
@@ -307,6 +307,21 @@ nsDisplayList::ComputeVisibilityForRoot(nsDisplayListBuilder* aBuilder,
   return ComputeVisibilityForSublist(aBuilder, aVisibleRegion, r.GetBounds());
 }
 
+static PRBool
+TreatAsOpaque(nsDisplayItem* aItem, nsDisplayListBuilder* aBuilder,
+              PRBool* aTransparentBackground)
+{
+  if (aItem->IsOpaque(aBuilder, aTransparentBackground))
+    return PR_TRUE;
+  if (aBuilder->IsForPluginGeometry()) {
+    // Treat all chrome items as opaque
+    nsIFrame* f = aItem->GetUnderlyingFrame();
+    if (f && f->PresContext()->IsChrome())
+      return PR_TRUE;
+  }
+  return PR_FALSE;
+}
+
 PRBool
 nsDisplayList::ComputeVisibilityForSublist(nsDisplayListBuilder* aBuilder,
                                            nsRegion* aVisibleRegion,
@@ -345,7 +360,7 @@ nsDisplayList::ComputeVisibilityForSublist(nsDisplayListBuilder* aBuilder,
       anyVisible = PR_TRUE;
       nsIFrame* f = item->GetUnderlyingFrame();
       PRBool transparentBackground = PR_FALSE;
-      if (item->IsOpaque(aBuilder, &transparentBackground) && f) {
+      if (TreatAsOpaque(item, aBuilder, &transparentBackground) && f) {
         // Subtract opaque item from the visible region
         aBuilder->SubtractFromVisibleRegion(aVisibleRegion, nsRegion(bounds));
       }
@@ -650,7 +665,8 @@ PRBool nsDisplayItem::RecomputeVisibility(nsDisplayListBuilder* aBuilder,
   if (!ComputeVisibility(aBuilder, aVisibleRegion))
     return PR_FALSE;
 
-  if (IsOpaque(aBuilder)) {
+  PRBool forceTransparentBackground;
+  if (TreatAsOpaque(this, aBuilder, &forceTransparentBackground)) {
     aVisibleRegion->Sub(*aVisibleRegion, bounds);
   }
   return PR_TRUE;
diff --git a/layout/base/nsDisplayList.h b/layout/base/nsDisplayList.h
index 84cbf1e0f0c..d2090f61076 100644
--- a/layout/base/nsDisplayList.h
+++ b/layout/base/nsDisplayList.h
@@ -136,15 +136,25 @@ public:
    * @param aBuildCaret whether or not we should include the caret in any
    * display lists that we make.
    */
-  nsDisplayListBuilder(nsIFrame* aReferenceFrame, PRBool aIsForEvents,
-                       PRBool aBuildCaret);
+  enum Mode {
+	PAINTING,
+	EVENT_DELIVERY,
+	PLUGIN_GEOMETRY,
+	OTHER
+  };
+  nsDisplayListBuilder(nsIFrame* aReferenceFrame, Mode aMode, PRBool aBuildCaret);
   ~nsDisplayListBuilder();
 
   /**
    * @return PR_TRUE if the display is being built in order to determine which
    * frame is under the mouse position.
    */
-  PRBool IsForEventDelivery() { return mEventDelivery; }
+  PRBool IsForEventDelivery() { return mMode == EVENT_DELIVERY; }
+  /**
+   * @return PR_TRUE if the display list is being build to compute geometry
+   * for plugins.
+   */
+  PRBool IsForPluginGeometry() { return mMode == PLUGIN_GEOMETRY; }
   /**
    * @return PR_TRUE if "painting is suppressed" during page load and we
    * should paint only the background of the document.
@@ -393,8 +403,8 @@ private:
   nsAutoTArray<PresShellState,8> mPresShellStates;
   nsAutoTArray<nsIFrame*,100>    mFramesMarkedForDisplay;
   nsDisplayTableItem*            mCurrentTableItem;
+  Mode                           mMode;
   PRPackedBool                   mBuildCaret;
-  PRPackedBool                   mEventDelivery;
   PRPackedBool                   mIgnoreSuppression;
   PRPackedBool                   mHadToIgnoreSuppression;
   PRPackedBool                   mIsAtRootOfPseudoStackingContext;
diff --git a/layout/base/nsLayoutUtils.cpp b/layout/base/nsLayoutUtils.cpp
index dd05d7847be..15650ca43ac 100644
--- a/layout/base/nsLayoutUtils.cpp
+++ b/layout/base/nsLayoutUtils.cpp
@@ -1093,7 +1093,8 @@ nsLayoutUtils::GetFramesForArea(nsIFrame* aFrame, const nsRect& aRect,
                                 PRBool aShouldIgnoreSuppression,
                                 PRBool aIgnoreRootScrollFrame)
 {
-  nsDisplayListBuilder builder(aFrame, PR_TRUE, PR_FALSE);
+  nsDisplayListBuilder builder(aFrame, nsDisplayListBuilder::EVENT_DELIVERY,
+		                       PR_FALSE);
   nsDisplayList list;
   nsRect target(aRect);
 
@@ -1266,7 +1267,8 @@ nsLayoutUtils::PaintFrame(nsIRenderingContext* aRenderingContext, nsIFrame* aFra
   // *and after* we draw.
   PRBool willFlushRetainedLayers = (aFlags & PAINT_HIDE_CARET) != 0;
 
-  nsDisplayListBuilder builder(aFrame, PR_FALSE, !(aFlags & PAINT_HIDE_CARET));
+  nsDisplayListBuilder builder(aFrame, nsDisplayListBuilder::PAINTING,
+		                       !(aFlags & PAINT_HIDE_CARET));
   nsDisplayList list;
   if (aFlags & PAINT_IN_TRANSFORM) {
     builder.SetInTransform(PR_TRUE);
diff --git a/layout/base/nsPresContext.cpp b/layout/base/nsPresContext.cpp
index 37bc60f6f08..968beab8fba 100644
--- a/layout/base/nsPresContext.cpp
+++ b/layout/base/nsPresContext.cpp
@@ -2520,7 +2520,8 @@ nsRootPresContext::GetPluginGeometryUpdates(nsIFrame* aChangedSubtree,
   nsRect bounds;
   if (bounds.IntersectRect(closure.mAffectedPluginBounds,
                            closure.mRootFrame->GetRect())) {
-    nsDisplayListBuilder builder(closure.mRootFrame, PR_FALSE, PR_FALSE);
+    nsDisplayListBuilder builder(closure.mRootFrame,
+    		nsDisplayListBuilder::PLUGIN_GEOMETRY, PR_FALSE);
     builder.SetAccurateVisibleRegions();
     nsDisplayList list;
 
diff --git a/layout/base/nsPresShell.cpp b/layout/base/nsPresShell.cpp
index 992ac9567c0..22ab07570f4 100644
--- a/layout/base/nsPresShell.cpp
+++ b/layout/base/nsPresShell.cpp
@@ -271,7 +271,7 @@ struct RangePaintInfo {
   nsPoint mRootOffset;
 
   RangePaintInfo(nsIRange* aRange, nsIFrame* aFrame)
-    : mRange(aRange), mBuilder(aFrame, PR_FALSE, PR_FALSE)
+    : mRange(aRange), mBuilder(aFrame, nsDisplayListBuilder::PAINTING, PR_FALSE)
   {
     MOZ_COUNT_CTOR(RangePaintInfo);
   }
diff --git a/layout/base/tests/chrome/Makefile.in b/layout/base/tests/chrome/Makefile.in
index e6d8fe32591..6167e6c4c59 100644
--- a/layout/base/tests/chrome/Makefile.in
+++ b/layout/base/tests/chrome/Makefile.in
@@ -53,6 +53,8 @@ _CHROME_FILES = \
 	bug551434_childframe.html \
 	test_chrome_content_integration.xul \
 	     chrome_content_integration_window.xul \
+	test_chrome_over_plugin.xul \
+	     chrome_over_plugin_window.xul \
 	test_default_background.xul \
 	     default_background_window.xul \
 	test_printpreview.xul \
diff --git a/layout/base/tests/chrome/chrome_over_plugin_window.xul b/layout/base/tests/chrome/chrome_over_plugin_window.xul
new file mode 100644
index 00000000000..b9792447c8b
--- /dev/null
+++ b/layout/base/tests/chrome/chrome_over_plugin_window.xul
@@ -0,0 +1,62 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<window title="Content/chrome integration subwindow"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+        onload="runTests()">\
+  <!-- We're mainly testing that a) translucent chrome elements cause the plugin to be clipped away and
+       b) translucent content elements do NOT cause the plugin to be clipped away -->
+  <stack style="height:100px; width:150px;">
+    <iframe type="content" style="border:none;" id="f"
+            src="data:text/html,&lt;embed id='e' type='application/x-test' wmode='window'
+                                style='position:absolute;left:0;top:0;width:100px;height:100px'&gt;&lt;/embed&gt;
+                                &lt;div style='position:absolute;left:0;top:80px;width:100px;height:10px;background:rgba(0,0,128,0.5)'&gt;&lt;/div&gt;
+                                &lt;div style='position:absolute;left:0;top:90px;width:100px;height:10px;background:blue'&gt;&lt;/div&gt;
+                                "/>
+    <vbox>
+      <vbox style="height:25px; background:yellow;"/> <!-- plugin should be covered here -->
+      <vbox style="height:25px; background:rgba(0,128,0,0.5);"/> <!-- plugin should be covered here -->
+      <vbox style="height:50px;"/> <!-- plugin should be visible here -->
+    </vbox>
+  </stack>
+
+  <script type="application/javascript">
+    <![CDATA[
+    var imports = [ "SimpleTest", "is", "isnot", "ok", "todo" ];
+    for each (var import in imports) {
+      window[import] = window.opener.wrappedJSObject[import];
+    }
+
+    var plugin;
+    function waitForPaint() {
+      if (plugin.getPaintCount() < 1) {
+        setTimeout(waitForPaint, 0);
+        return;
+      }
+
+      if (plugin.hasWidget()) {
+        is(plugin.getClipRegionRectCount(), 1, "plugin clip rect count");
+        var left = plugin.getEdge(0);
+        var top = plugin.getEdge(1);
+        is(plugin.getClipRegionRectEdge(0,0) - left, 0, "plugin clip rect left");
+        // our two vboxes with backgrounds should cause the top of the plugin to be clipped
+        is(plugin.getClipRegionRectEdge(0,1) - top, 50, "plugin clip rect top");
+        is(plugin.getClipRegionRectEdge(0,2) - left, 100, "plugin clip rect right");
+        // of the two content DIVs, the first one should not cause the plugin to be clipped because
+        // it's transparent. The second one should cause the plugin to be clipped.
+        is(plugin.getClipRegionRectEdge(0,3) - top, 90, "plugin clip rect bottom");
+      } else {
+        todo(false, "Test only tests windowed plugins");
+      }
+
+      var tester = window.SimpleTest;
+      window.close();
+      tester.finish();
+    }
+
+    function runTests() {
+      plugin = document.getElementById("f").contentDocument.getElementById("e").wrappedJSObject;
+      waitForPaint();
+    }
+    ]]>
+  </script>
+</window>
diff --git a/layout/base/tests/chrome/test_chrome_over_plugin.xul b/layout/base/tests/chrome/test_chrome_over_plugin.xul
new file mode 100644
index 00000000000..abf49dd0e7e
--- /dev/null
+++ b/layout/base/tests/chrome/test_chrome_over_plugin.xul
@@ -0,0 +1,25 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script type="application/javascript"
+          src="chrome://mochikit/content/MochiKit/packed.js"></script>
+  <script type="application/javascript"
+          src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+    SimpleTest.waitForExplicitFinish();
+    // Run the test in a separate window so that the test runs as a chrome
+    // window
+    var w = window.open("chrome_over_plugin_window.xul", "chrome_over_plugin",
+                         "chrome,width=200,height=300");
+  ]]>
+  </script>
+</window>
diff --git a/layout/generic/nsGfxScrollFrame.cpp b/layout/generic/nsGfxScrollFrame.cpp
index 21821c9955b..13207ff9241 100644
--- a/layout/generic/nsGfxScrollFrame.cpp
+++ b/layout/generic/nsGfxScrollFrame.cpp
@@ -1553,7 +1553,7 @@ InvalidateFixedBackgroundFrames(nsIFrame* aRootFrame,
                "The root frame shouldn't be the one that's moving, that makes no sense");
 
   // Build the 'after' display list over the whole area of interest.
-  nsDisplayListBuilder builder(aRootFrame, PR_FALSE, PR_TRUE);
+  nsDisplayListBuilder builder(aRootFrame, nsDisplayListBuilder::OTHER, PR_TRUE);
   builder.EnterPresShell(aRootFrame, aUpdateRect);
   nsDisplayList list;
   nsresult rv =
diff --git a/layout/generic/nsObjectFrame.cpp b/layout/generic/nsObjectFrame.cpp
index 48a5f0a5068..3ec7ed3be3e 100644
--- a/layout/generic/nsObjectFrame.cpp
+++ b/layout/generic/nsObjectFrame.cpp
@@ -1273,6 +1273,22 @@ nsDisplayPlugin::IsOpaque(nsDisplayListBuilder* aBuilder,
     *aForceTransparentSurface = PR_FALSE;
   }
   nsObjectFrame* f = static_cast<nsObjectFrame*>(mFrame);
+  if (!aBuilder->IsForPluginGeometry()) {
+    nsIWidget* widget = f->GetWidget();
+    if (widget) {
+      nsTArray<nsIntRect> clip;
+      widget->GetWindowClipRegion(&clip);
+      nsTArray<nsIWidget::Configuration> configuration;
+      GetWidgetConfiguration(aBuilder, &configuration);
+      NS_ASSERTION(configuration.Length() == 1, "No configuration found");
+      if (clip != configuration[0].mClipRegion) {
+        // Something has clipped us unexpectedly. Perhaps there is a translucent
+        // chrome element overlaying us that forced us to be clipped away. Treat
+        // us as non-opaque since we may have holes.
+    	return PR_FALSE;
+      }
+    }
+  }
   return f->IsOpaque();
 }
 
diff --git a/xpcom/glue/nsTArray.h b/xpcom/glue/nsTArray.h
index ecc143f668e..60f37e269d7 100644
--- a/xpcom/glue/nsTArray.h
+++ b/xpcom/glue/nsTArray.h
@@ -313,6 +313,12 @@ class nsTArray : public nsTArray_base {
       return true;
     }
 
+    // Return true if this array does not have the same length and the same
+    // elements as |other|.
+    bool operator!=(const self_type& other) const {
+      return !operator==(other);
+    }
+
     //
     // Accessor methods
     //