Bug 689623. Part 8. Add an 'unlocked draw' notification for images that are drawn when not locked so we catch any images that become visible through a means other than scrolling. r=joe,mats

content/base/src/nsImageLoadingContent.cpp

@@ -122,6 +122,11 @@ nsImageLoadingContent::Notify(imgIRequest* aRequest,
     return OnImageIsAnimated(aRequest);
   }
 
+  if (aType == imgINotificationObserver::UNLOCKED_DRAW) {
+    OnUnlockedDraw();
+    return NS_OK;
+  }
+
   if (aType == imgINotificationObserver::LOAD_COMPLETE) {
     // We should definitely have a request here
     NS_ABORT_IF_FALSE(aRequest, "no request?");
@@ -229,6 +234,20 @@ nsImageLoadingContent::OnStopRequest(imgIRequest* aRequest,
   return NS_OK;
 }
 
+void
+nsImageLoadingContent::OnUnlockedDraw()
+{
+  nsPresContext* presContext = GetFramePresContext();
+  if (!presContext)
+    return;
+
+  nsIPresShell* presShell = presContext->PresShell();
+  if (!presShell)
+    return;
+
+  presShell->EnsureImageInVisibleList(this);
+}
+
 nsresult
 nsImageLoadingContent::OnImageIsAnimated(imgIRequest *aRequest)
 {

content/base/src/nsImageLoadingContent.h

@@ -183,6 +183,7 @@ protected:
   void UnbindFromTree(bool aDeep, bool aNullParent);
 
   nsresult OnStopRequest(imgIRequest* aRequest, nsresult aStatus);
+  void OnUnlockedDraw();
   nsresult OnImageIsAnimated(imgIRequest *aRequest);
 
 private:

image/public/imgINotificationObserver.idl

@@ -14,7 +14,7 @@ interface imgIRequest;
 
 [ptr] native nsIntRect(nsIntRect);
 
-[scriptable, builtinclass, uuid(90b3d21c-317d-4d96-93c0-12add64a26bf)]
+[scriptable, builtinclass, uuid(ac65c702-7771-4f6d-b18b-1c7d806ce3c1)]
 interface imgINotificationObserver : nsISupports
 {
   const long SIZE_AVAILABLE = 1;
@@ -23,7 +23,8 @@ interface imgINotificationObserver : nsISupports
   const long LOAD_COMPLETE = 4;
   const long DECODE_COMPLETE = 5;
   const long DISCARD = 6;
-  const long IS_ANIMATED = 7;
+  const long UNLOCKED_DRAW = 7;
+  const long IS_ANIMATED = 8;
 
   [noscript] void notify(in imgIRequest aProxy, in long aType, [const] in nsIntRect aRect);
 };

image/src/RasterImage.cpp

@@ -3107,6 +3107,15 @@ RasterImage::Draw(gfxContext *aContext,
     DiscardTracker::Reset(&mDiscardTrackerNode);
   }
 
+  // We would like to just check if we have a zero lock count, but we can't do
+  // that for animated images because in EnsureAnimExists we lock the image and
+  // never unlock so that animated images always have their lock count >= 1. In
+  // that case we use our animation consumers count as a proxy for lock count.
+  if (mLockCount == 0 || (mAnim && mAnimationConsumers == 0)) {
+    if (mStatusTracker)
+      mStatusTracker->GetDecoderObserver()->OnUnlockedDraw();
+  }
+
   // We use !mDecoded && mHasSourceData to mean discarded.
   if (!mDecoded && mHasSourceData) {
       mDrawStartTime = TimeStamp::Now();

image/src/imgDecoderObserver.h

@@ -109,6 +109,11 @@ public:
    * image will initiate a new series of progressive decode notifications.
    */
   virtual void OnDiscard() = 0;
+
+  /**
+   * Called when we are asked to Draw an image that is not locked.
+   */
+  virtual void OnUnlockedDraw() = 0;
 };
 
 // We must define a destructor because derived classes call our destructor from

image/src/imgRequestProxy.cpp

@@ -767,6 +767,17 @@ void imgRequestProxy::OnDiscard()
   }
 }
 
+void imgRequestProxy::OnUnlockedDraw()
+{
+  LOG_FUNC(GetImgLog(), "imgRequestProxy::OnUnlockedDraw");
+
+  if (mListener && !mCanceled) {
+    // Hold a ref to the listener while we call it, just in case.
+    nsCOMPtr<imgINotificationObserver> kungFuDeathGrip(mListener);
+    mListener->Notify(this, imgINotificationObserver::UNLOCKED_DRAW, nullptr);
+  }
+}
+
 void imgRequestProxy::OnImageIsAnimated()
 {
   LOG_FUNC(GetImgLog(), "imgRequestProxy::OnImageIsAnimated");

image/src/imgRequestProxy.h

@@ -143,6 +143,7 @@ protected:
   void OnStopFrame       ();
   void OnStopDecode      ();
   void OnDiscard         ();
+  void OnUnlockedDraw    ();
   void OnImageIsAnimated ();
 
   /* non-virtual sort-of-nsIRequestObserver methods */

image/src/imgStatusTracker.cpp

@@ -165,6 +165,18 @@ public:
     }
   }
 
+  virtual void OnUnlockedDraw()
+  {
+    NS_ABORT_IF_FALSE(mTracker->GetImage(),
+                      "OnUnlockedDraw callback before we've created our image");
+    mTracker->RecordUnlockedDraw();
+
+    nsTObserverArray<imgRequestProxy*>::ForwardIterator iter(mTracker->mConsumers);
+    while (iter.HasMore()) {
+      mTracker->SendUnlockedDraw(iter.GetNext());
+    }
+  }
+
   virtual void OnImageIsAnimated()
   {
     NS_ABORT_IF_FALSE(mTracker->GetImage(),
@@ -568,6 +580,13 @@ imgStatusTracker::RecordDiscard()
   mImageStatus &= ~statusBitsToClear;
 }
 
+void
+imgStatusTracker::RecordUnlockedDraw()
+{
+  NS_ABORT_IF_FALSE(mImage,
+                    "RecordUnlockedDraw called before we have an Image");
+}
+
 void
 imgStatusTracker::SendImageIsAnimated(imgRequestProxy* aProxy)
 {
@@ -593,6 +612,13 @@ imgStatusTracker::SendDiscard(imgRequestProxy* aProxy)
     aProxy->OnDiscard();
 }
 
+void
+imgStatusTracker::SendUnlockedDraw(imgRequestProxy* aProxy)
+{
+  if (!aProxy->NotificationsDeferred())
+    aProxy->OnUnlockedDraw();
+}
+
 void
 imgStatusTracker::RecordFrameChanged(const nsIntRect* aDirtyRect)
 {

image/src/imgStatusTracker.h

@@ -145,6 +145,8 @@ public:
   void SendStopDecode(imgRequestProxy* aProxy, nsresult aStatus);
   void RecordDiscard();
   void SendDiscard(imgRequestProxy* aProxy);
+  void RecordUnlockedDraw();
+  void SendUnlockedDraw(imgRequestProxy* aProxy);
   void RecordImageIsAnimated();
   void SendImageIsAnimated(imgRequestProxy *aProxy);
 

layout/base/nsIPresShell.h

@@ -38,6 +38,7 @@
 #include "nsInterfaceHashtable.h"
 #include "nsEventStates.h"
 #include "nsPresArena.h"
+#include "nsIImageLoadingContent.h"
 
 class nsIContent;
 class nsIDocument;
@@ -120,10 +121,10 @@ typedef struct CapturingContentInfo {
   nsIContent* mContent;
 } CapturingContentInfo;
 
-// 15f6c268-e40f-42a9-a7eb-e5e10a5840a1
+// 835b3946-1a4f-4132-b3ce-2e2e8be377c8
 #define NS_IPRESSHELL_IID \
-{ 0x15f6c268, 0xe40f, 0x42a9, \
-  { 0xa7, 0xeb, 0xe5, 0xe1, 0x0a, 0x58, 0x40, 0xa1 } }
+{ 0x835b3946, 0x1a4f, 0x4132, \
+  { 0xb3, 0xce, 0x2e, 0x2e, 0x8b, 0xe3, 0x77, 0xc8 } }
 
 // debug VerifyReflow flags
 #define VERIFY_REFLOW_ON                    0x01
@@ -1327,6 +1328,9 @@ public:
   // with images that are in the display list aList.
   virtual void RebuildImageVisibility(const nsDisplayList& aList) = 0;
 
+  // Ensures the image is in the list of visible images.
+  virtual void EnsureImageInVisibleList(nsIImageLoadingContent* aImage) = 0;
+
   /**
    * Refresh observer management.
    */

layout/base/nsPresShell.cpp

@@ -5415,6 +5415,27 @@ PresShell::ScheduleImageVisibilityUpdate()
   }
 }
 
+void
+PresShell::EnsureImageInVisibleList(nsIImageLoadingContent* aImage)
+{
+#ifdef DEBUG
+  // if it has a frame make sure its in this presshell
+  nsCOMPtr<nsIContent> content = do_QueryInterface(aImage);
+  if (content) {
+    PresShell* shell = static_cast<PresShell*>(content->OwnerDoc()->GetShell());
+    MOZ_ASSERT(!shell || shell == this, "wrong shell");
+  }
+#endif
+
+  // This check could be slow.
+  if (mVisibleImages.Contains(aImage)) {
+    return;
+  }
+
+  mVisibleImages.AppendElement(aImage);
+  aImage->IncrementVisibleCount();
+}
+
 class nsAutoNotifyDidPaint
 {
 public:

layout/base/nsPresShell.h

@@ -339,6 +339,8 @@ public:
 
   virtual void RebuildImageVisibility(const nsDisplayList& aList);
 
+  virtual void EnsureImageInVisibleList(nsIImageLoadingContent* aImage);
+
 protected:
   virtual ~PresShell();