WebKit::DisplayLink maintains a strong reference to WebPageProxy, creating a reference cycle

shultzc · shultzc · commit fe3ff014b76e · 2018-04-18T03:07:10.000Z
https://bugs.webkit.org/show_bug.cgi?id=184718 Reviewed by Tim Horton. It turns out that the m_webPageProxy back-reference in DisplayLink, which was creating a reference cycle, wasn't ever read, so we can just remove it. * UIProcess/mac/DisplayLink.cpp: (WebKit::DisplayLink::DisplayLink): * UIProcess/mac/DisplayLink.h: Canonical link: https://commits.webkit.org/200233@main git-svn-id: https://svn.webkit.org/repository/webkit/trunk@230747 268f45cc-cd09-0410-ab3c-d52691b4dbfc
diff --git a/Source/WebKit/ChangeLog b/Source/WebKit/ChangeLog
@@ -1,3 +1,17 @@
+2018-04-17  Conrad Shultz  <conrad_shultz@apple.com>
+
+        WebKit::DisplayLink maintains a strong reference to WebPageProxy, creating a reference cycle
+        https://bugs.webkit.org/show_bug.cgi?id=184718
+
+        Reviewed by Tim Horton.
+
+        It turns out that the m_webPageProxy back-reference in DisplayLink, which was creating a
+        reference cycle, wasn't ever read, so we can just remove it.
+
+        * UIProcess/mac/DisplayLink.cpp:
+        (WebKit::DisplayLink::DisplayLink):
+        * UIProcess/mac/DisplayLink.h:
+
 2018-04-17  Wenson Hsieh  <wenson_hsieh@apple.com>
 
         [Extra zoom mode] Double tap to zoom should account for text legibility in extra zoom mode
diff --git a/Source/WebKit/UIProcess/mac/DisplayLink.cpp b/Source/WebKit/UIProcess/mac/DisplayLink.cpp
@@ -36,7 +36,6 @@
 namespace WebKit {
     
 DisplayLink::DisplayLink(WebCore::PlatformDisplayID displayID, WebPageProxy& webPageProxy)
-    : m_webPageProxy(webPageProxy)
 {
     RELEASE_ASSERT(hasProcessPrivilege(ProcessPrivilege::CanCommunicateWithWindowServer));
     CVReturn error = CVDisplayLinkCreateWithCGDisplay(displayID, &m_displayLink);
diff --git a/Source/WebKit/UIProcess/mac/DisplayLink.h b/Source/WebKit/UIProcess/mac/DisplayLink.h
@@ -49,7 +49,6 @@ class DisplayLink {
     static CVReturn displayLinkCallback(CVDisplayLinkRef, const CVTimeStamp*, const CVTimeStamp*, CVOptionFlags, CVOptionFlags*, void* data);
     
     CVDisplayLinkRef m_displayLink { nullptr };
-    Ref<WebPageProxy> m_webPageProxy;
     HashSet<unsigned> m_observers;
 };
 

Original file line number	Diff line number	Diff line change
`@@ -36,7 +36,6 @@`
`36`	`36`	`namespace WebKit {`
`37`	`37`
`38`	`38`	`DisplayLink::DisplayLink(WebCore::PlatformDisplayID displayID, WebPageProxy& webPageProxy)`
`39`		`- : m_webPageProxy(webPageProxy)`
`40`	`39`	`{`
`41`	`40`	`RELEASE_ASSERT(hasProcessPrivilege(ProcessPrivilege::CanCommunicateWithWindowServer));`
`42`	`41`	`CVReturn error = CVDisplayLinkCreateWithCGDisplay(displayID, &m_displayLink);`