Merge r243505 - Assertion failure !isInAcceleratedCompositingMode() i…

…n DrawingAreaProxyCoordinatedGraphics::incorporateUpdate when forceCompositingMode is turned on

https://bugs.webkit.org/show_bug.cgi?id=195879

Patch by Tomoki Imai <Tomoki.Imai@sony.com> on 2019-03-26
Reviewed by Carlos Garcia Campos.

The root cause is that DrawingAreaProxyCoordinatedGraphics::isInAcceleratedCompositingMode checks both of alwaysUseCompositing() and !m_layerTreeContext.isEmpty().
alwaysUseCompositing() refers preferences, which is written by the application (UIProcess).
On the other hand, m_layerTreeContext is changed when it receives enterAcceleratedCompositingMode/exitAcceleratedCompositingMode from WebProcess.

It results when we set forceCompositingMode and acceleratedCompositingEnabled to true, WebProcess and UIProcess is out of sync until WebProcess sends enterAcceleratedCompositingMode message.
In such situation, WebProcess sends incorporateUpdate to UIProcess because WebProcess is in non-AC mode, but isInAcceleratedCompositingMode becomes true in UIProcess side.

* UIProcess/CoordinatedGraphics/DrawingAreaProxyCoordinatedGraphics.cpp:
(WebKit::DrawingAreaProxyCoordinatedGraphics::~DrawingAreaProxyCoordinatedGraphics): Should call exitAcceleratedCompositingMode even when alwaysUseCompositing is true.
(WebKit::DrawingAreaProxyCoordinatedGraphics::enterAcceleratedCompositingMode): enterAcceleratedCompositingMode should check enterAcceleratedCompositingMode is not called twice.
* UIProcess/CoordinatedGraphics/DrawingAreaProxyCoordinatedGraphics.h: Remove alwaysUseCompositing from isInAcceleratedCompositingMode

Source/WebKit/ChangeLog

@@ -1,3 +1,22 @@
+2019-03-26  Tomoki Imai  <Tomoki.Imai@sony.com>
+
+        Assertion failure !isInAcceleratedCompositingMode() in DrawingAreaProxyCoordinatedGraphics::incorporateUpdate when forceCompositingMode is turned on
+        https://bugs.webkit.org/show_bug.cgi?id=195879
+
+        Reviewed by Carlos Garcia Campos.
+
+        The root cause is that DrawingAreaProxyCoordinatedGraphics::isInAcceleratedCompositingMode checks both of alwaysUseCompositing() and !m_layerTreeContext.isEmpty().
+        alwaysUseCompositing() refers preferences, which is written by the application (UIProcess).
+        On the other hand, m_layerTreeContext is changed when it receives enterAcceleratedCompositingMode/exitAcceleratedCompositingMode from WebProcess.
+
+        It results when we set forceCompositingMode and acceleratedCompositingEnabled to true, WebProcess and UIProcess is out of sync until WebProcess sends enterAcceleratedCompositingMode message.
+        In such situation, WebProcess sends incorporateUpdate to UIProcess because WebProcess is in non-AC mode, but isInAcceleratedCompositingMode becomes true in UIProcess side.
+
+        * UIProcess/CoordinatedGraphics/DrawingAreaProxyCoordinatedGraphics.cpp:
+        (WebKit::DrawingAreaProxyCoordinatedGraphics::~DrawingAreaProxyCoordinatedGraphics): Should call exitAcceleratedCompositingMode even when alwaysUseCompositing is true.
+        (WebKit::DrawingAreaProxyCoordinatedGraphics::enterAcceleratedCompositingMode): enterAcceleratedCompositingMode should check enterAcceleratedCompositingMode is not called twice.
+        * UIProcess/CoordinatedGraphics/DrawingAreaProxyCoordinatedGraphics.h: Remove alwaysUseCompositing from isInAcceleratedCompositingMode
+
 2019-04-03  Carlos Garcia Campos  <cgarcia@igalia.com>
 
         [CoordinatedGraphics] Hidden pages are not suspended after a web view resize

Source/WebKit/UIProcess/CoordinatedGraphics/DrawingAreaProxyCoordinatedGraphics.cpp

@@ -67,7 +67,7 @@ DrawingAreaProxyCoordinatedGraphics::DrawingAreaProxyCoordinatedGraphics(WebPage
 DrawingAreaProxyCoordinatedGraphics::~DrawingAreaProxyCoordinatedGraphics()
 {
     // Make sure to exit accelerated compositing mode.
-    if (isInAcceleratedCompositingMode() && !alwaysUseCompositing())
+    if (isInAcceleratedCompositingMode())
         exitAcceleratedCompositingMode();
 }
 
@@ -269,7 +269,7 @@ bool DrawingAreaProxyCoordinatedGraphics::alwaysUseCompositing() const
 
 void DrawingAreaProxyCoordinatedGraphics::enterAcceleratedCompositingMode(const LayerTreeContext& layerTreeContext)
 {
-    ASSERT(alwaysUseCompositing() || !isInAcceleratedCompositingMode());
+    ASSERT(!isInAcceleratedCompositingMode());
 #if !PLATFORM(WPE)
     m_backingStore = nullptr;
 #endif

Source/WebKit/UIProcess/CoordinatedGraphics/DrawingAreaProxyCoordinatedGraphics.h

@@ -47,7 +47,7 @@ class DrawingAreaProxyCoordinatedGraphics final : public DrawingAreaProxy {
     void paint(BackingStore::PlatformGraphicsContext, const WebCore::IntRect&, WebCore::Region& unpaintedRegion);
 #endif
 
-    bool isInAcceleratedCompositingMode() const { return alwaysUseCompositing() || !m_layerTreeContext.isEmpty(); }
+    bool isInAcceleratedCompositingMode() const { return !m_layerTreeContext.isEmpty(); }
 
 #if USE(TEXTURE_MAPPER_GL) && PLATFORM(GTK) && PLATFORM(X11) && !USE(REDIRECTED_XCOMPOSITE_WINDOW)
     void setNativeSurfaceHandleForCompositing(uint64_t);