Changeset 156200 in webkit

Timestamp:

Sep 20, 2013, 2:47:38 PM (12 years ago)

Author:

Simon Fraser

Message:

Ensure that TileController tile coverage is updated on scrolling even when we don't have scrollbars
​https://bugs.webkit.org/show_bug.cgi?id=121700
<rdar://problem/15030589>

Reviewed by Dean Jackson.

r155660 introduced a bug where we wouldn't make scrollbars on long pages. However,
that revealed a fundamental flaw in the TiledBacking update logic; it relied on the
GraphicsLayer flushes triggered by scrollbars updates in order to update the main
TileController's tile coverage. No scrollbars meant no tile coverage updates.

Fix by explicitly triggering a flush when the FrameView is scrolled (we get
notified about this on the main thread after the scrolling thread has moved
layers around).

No test since this will only be exposed for a short time while scrollbars are
broken.

• rendering/RenderLayerCompositor.cpp:

(WebCore::RenderLayerCompositor::frameViewDidScroll):

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• rendering/RenderLayerCompositor.cpp (modified) (1 diff)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2013-09-20  Simon Fraser  <simon.fraser@apple.com>
+
+        Ensure that TileController tile coverage is updated on scrolling even when we don't have scrollbars
+        https://bugs.webkit.org/show_bug.cgi?id=121700
+        <rdar://problem/15030589>
+
+        Reviewed by Dean Jackson.
+
+        r155660 introduced a bug where we wouldn't make scrollbars on long pages. However,
+        that revealed a fundamental flaw in the TiledBacking update logic; it relied on the
+        GraphicsLayer flushes triggered by scrollbars updates in order to update the main
+        TileController's tile coverage. No scrollbars meant no tile coverage updates.
+        
+        Fix by explicitly triggering a flush when the FrameView is scrolled (we get
+        notified about this on the main thread after the scrolling thread has moved
+        layers around).
+        
+        No test since this will only be exposed for a short time while scrollbars are
+        broken.
+
+        * rendering/RenderLayerCompositor.cpp:
+        (WebCore::RenderLayerCompositor::frameViewDidScroll):
+
 2013-09-20  Zoltan Horvath  <zoltan@webkit.org>
 

trunk/Source/WebCore/rendering/RenderLayerCompositor.cpp

@@ -1320 +1320 @@
     // If there's a scrolling coordinator that manages scrolling for this frame view,
     // it will also manage updating the scroll layer position.
-    if (hasCoordinatedScrolling())
-        return;
+    if (hasCoordinatedScrolling()) {
+        // We have to schedule a flush in order for the main TiledBacking to update its tile coverage.
+        scheduleLayerFlushNow();
+        return;
+    }
 
     FrameView& frameView = m_renderView.frameView();