Bug 1346501. Don't mark every image as visible when a frame is created for it

2 files changed, 25 insertions, 11 deletions

diff --git a/dom/base/nsImageLoadingContent.cpp b/dom/base/nsImageLoadingContent.cpp
index d25dd6319..b76bc533f 100644
--- a/dom/base/nsImageLoadingContent.cpp
+++ b/dom/base/nsImageLoadingContent.cpp
@@ -491,8 +491,8 @@ nsImageLoadingContent::FrameCreated(nsIFrame* aFrame)
 
   mFrameCreateCalled = true;
 
-  TrackImage(mCurrentRequest);
-  TrackImage(mPendingRequest);
+  TrackImage(mCurrentRequest, aFrame);
+  TrackImage(mPendingRequest, aFrame);
 
   // We need to make sure that our image request is registered, if it should
   // be registered.
@@ -1486,7 +1486,8 @@ nsImageLoadingContent::OnVisibilityChange(Visibility aNewVisibility,
 }
 
 void
-nsImageLoadingContent::TrackImage(imgIRequest* aImage)
+nsImageLoadingContent::TrackImage(imgIRequest* aImage,
+                                  nsIFrame* aFrame /*= nullptr */)
 {
   if (!aImage)
     return;
@@ -1499,13 +1500,21 @@ nsImageLoadingContent::TrackImage(imgIRequest* aImage)
     return;
   }
 
-  // We only want to track this request if we're visible. Ordinarily we check
-  // the visible count, but that requires a frame; in cases where
-  // GetOurPrimaryFrame() cannot obtain a frame (e.g. <feImage>), we assume
-  // we're visible if FrameCreated() was called.
-  nsIFrame* frame = GetOurPrimaryFrame();
-  if ((frame && frame->GetVisibility() == Visibility::APPROXIMATELY_NONVISIBLE) ||
-      (!frame && !mFrameCreateCalled)) {
+  if (!aFrame) {
+    aFrame = GetOurPrimaryFrame();
+  }
+
+  /* This line is deceptively simple. It hides a lot of subtlety. Before we
+   * create an nsImageFrame we call nsImageFrame::ShouldCreateImageFrameFor
+   * to determine if we should create an nsImageFrame or create a frame based
+   * on the display of the element (ie inline, block, etc). Inline, block, etc
+   * frames don't register for visibility tracking so they will return UNTRACKED
+   * from GetVisibility(). So this line is choosing to mark such images as
+   * visible. Once the image loads we will get an nsImageFrame and the proper
+   * visibility. This is a pitfall of tracking the visibility on the frames
+   * instead of the content node.
+   */
+  if (!aFrame || aFrame->GetVisibility() == Visibility::APPROXIMATELY_NONVISIBLE) {
     return;
   }
 
diff --git a/dom/base/nsImageLoadingContent.h b/dom/base/nsImageLoadingContent.h
index 85db2bd2c..0764d425c 100644
--- a/dom/base/nsImageLoadingContent.h
+++ b/dom/base/nsImageLoadingContent.h
@@ -364,6 +364,11 @@ protected:
    *
    * No-op if aImage is null.
    *
+   * @param aFrame If called from FrameCreated the frame passed to FrameCreated.
+   *               This is our frame, but at the time of the FrameCreated call
+   *               our primary frame pointer hasn't been set yet, so this is
+   *               only way to get our frame.
+   *
    * @param aNonvisibleAction A requested action if the frame has become
    *                          nonvisible. If Nothing(), no action is
    *                          requested. If DISCARD_IMAGES is specified, the
@@ -371,7 +376,7 @@ protected:
    *                          associated with to discard their surfaces if
    *                          possible.
    */
-  void TrackImage(imgIRequest* aImage);
+  void TrackImage(imgIRequest* aImage, nsIFrame* aFrame = nullptr);
   void UntrackImage(imgIRequest* aImage,
                     const Maybe<OnNonvisible>& aNonvisibleAction = Nothing());