Don't invalidate paint on background image change if it's obscured

third_party/WebKit/Source/core/layout/LayoutImage.cpp

Index: third_party/WebKit/Source/core/layout/LayoutImage.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutImage.cpp b/third_party/WebKit/Source/core/layout/LayoutImage.cpp
index e2c218ee307c366118ab6f71b3422e6b565abd64..41032bd16efc128b49743304bb8253b84473600a 100644
--- a/third_party/WebKit/Source/core/layout/LayoutImage.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutImage.cpp
@@ -216,7 +216,7 @@ bool LayoutImage::foregroundIsKnownToBeOpaqueInRect(const LayoutRect& localRect,
 {
     if (!m_imageResource->hasImage() || m_imageResource->errorOccurred())
         return false;
-    if (m_imageResource->cachedImage() && !m_imageResource->cachedImage()->isLoaded())
+    if (!m_imageResource->cachedImage() || !m_imageResource->cachedImage()->isLoaded())
         return false;
     if (!contentBoxRect().contains(localRect))
         return false;
@@ -234,8 +234,6 @@ bool LayoutImage::foregroundIsKnownToBeOpaqueInRect(const LayoutRect& localRect,
     ObjectFit objectFit = style()->getObjectFit();
     if (objectFit != ObjectFitFill && objectFit != ObjectFitCover)
         return false;
-    if (!m_imageResource->cachedImage())

[chrishtr, 2016/08/09 16:05:17]

?

[Xianzhu, 2016/08/09 18:51:48]

This is combined into the condition at line 219.

[chrishtr, 2016/08/09 22:07:54]

Ah ok.

-        return false;
     // Check for image with alpha.
     TRACE_EVENT1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline"), "PaintImage", "data", InspectorPaintImageEvent::data(this, *m_imageResource->cachedImage()));
     return m_imageResource->cachedImage()->getImage()->currentFrameKnownToBeOpaque(Image::PreCacheMetadata);