Revert of Remove WebViewImpl::setIsAcceleratedCompositingActive

Source/web/WebViewImpl.cpp

Index: Source/web/WebViewImpl.cpp
diff --git a/Source/web/WebViewImpl.cpp b/Source/web/WebViewImpl.cpp
index a026fe12d901b713238940b116dec3d146e18902..8cadf7fe2abd507641b75a6bb3f7d9d28e9c0a81 100644
--- a/Source/web/WebViewImpl.cpp
+++ b/Source/web/WebViewImpl.cpp
@@ -340,14 +340,10 @@
 
 void WebViewImpl::setMainFrame(WebFrame* frame)
 {
-    if (frame->isWebLocalFrame()) {
-        WebLocalFrameImpl* localFrame = toWebLocalFrameImpl(frame);
-        localFrame->initializeCoreFrame(&page()->frameHost(), 0, nullAtom, nullAtom);
-        // Composited WebViews want repaints outside the frame visible rect.
-        localFrame->frame()->view()->setClipsRepaints(!m_layerTreeView);
-    } else {
+    if (frame->isWebLocalFrame())
+        toWebLocalFrameImpl(frame)->initializeCoreFrame(&page()->frameHost(), 0, nullAtom, nullAtom);
+    else
         toWebRemoteFrameImpl(frame)->initializeCoreFrame(&page()->frameHost(), 0, nullAtom);
-    }
 }
 
 void WebViewImpl::setCredentialManagerClient(WebCredentialManagerClient* webCredentialManagerClient)
@@ -416,13 +412,19 @@
     , m_rootGraphicsLayer(0)
     , m_rootTransformLayer(0)
     , m_graphicsLayerFactory(adoptPtr(new GraphicsLayerFactoryChromium(this)))
+    , m_isAcceleratedCompositingActive(false)
+    , m_layerTreeViewCommitsDeferred(false)
+    , m_layerTreeViewClosed(false)
     , m_matchesHeuristicsForGpuRasterization(false)
     , m_recreatingGraphicsContext(false)
     , m_flingModifier(0)
     , m_flingSourceDevice(false)
     , m_fullscreenController(FullscreenController::create(this))
     , m_showFPSCounter(false)
+    , m_showPaintRects(false)
+    , m_showDebugBorders(false)
     , m_continuousPaintingEnabled(false)
+    , m_showScrollBottleneckRects(false)
     , m_baseBackgroundColor(Color::white)
     , m_backgroundColorOverride(Color::transparent)
     , m_zoomFactorOverride(0)
@@ -965,6 +967,7 @@
         TRACE_EVENT0("blink", "WebViewImpl::setShowPaintRects");
         m_layerTreeView->setShowPaintRects(show);
     }
+    m_showPaintRects = show;
     setFirstPaintInvalidationTrackingEnabledForShowPaintRects(show);
 }
 
@@ -972,6 +975,7 @@
 {
     if (m_layerTreeView)
         m_layerTreeView->setShowDebugBorders(show);
+    m_showDebugBorders = show;
 }
 
 void WebViewImpl::setContinuousPaintingEnabled(bool enabled)
@@ -999,6 +1003,7 @@
 {
     if (m_layerTreeView)
         m_layerTreeView->setShowScrollBottleneckRects(show);
+    m_showScrollBottleneckRects = show;
 }
 
 void WebViewImpl::acceptLanguagesChanged()
@@ -2727,12 +2732,14 @@
 
 bool WebViewImpl::isAcceleratedCompositingActive() const
 {
-    return m_rootLayer;
+    return m_isAcceleratedCompositingActive;
 }
 
 void WebViewImpl::willCloseLayerTreeView()
 {
+    setIsAcceleratedCompositingActive(false);
     m_layerTreeView = 0;
+    m_layerTreeViewClosed = true;
 }
 
 void WebViewImpl::didAcquirePointerLock()
@@ -3699,7 +3706,7 @@
     }
 
     if (m_client) {
-        if (m_layerTreeView) {
+        if (isAcceleratedCompositingActive()) {
             updateLayerTreeViewport();
         } else {
             WebRect damagedRect(0, 0, m_size.width, m_size.height);
@@ -3847,9 +3854,6 @@
 
     // Future frames check this to know whether to be transparent.
     m_isTransparent = isTransparent;
-
-    if (m_layerTreeView)
-        m_layerTreeView->setHasTransparentBackground(this->isTransparent());
 }
 
 bool WebViewImpl::isTransparent() const
@@ -3950,8 +3954,11 @@
 
 void WebViewImpl::resumeTreeViewCommits()
 {
-    if (m_layerTreeView)
-        m_layerTreeView->setDeferCommits(false);
+    if (m_layerTreeViewCommitsDeferred) {
+        if (m_layerTreeView)
+            m_layerTreeView->setDeferCommits(false);
+        m_layerTreeViewCommitsDeferred = false;
+    }
 }
 
 void WebViewImpl::postLayoutResize(WebLocalFrameImpl* webframe)
@@ -4147,9 +4154,6 @@
 
 void WebViewImpl::setRootGraphicsLayer(GraphicsLayer* layer)
 {
-    if (!m_layerTreeView)
-        return;
-
     suppressInvalidations(true);
 
     PinchViewport& pinchViewport = page()->frameHost().pinchViewport();
@@ -4158,16 +4162,15 @@
         m_rootGraphicsLayer = pinchViewport.rootGraphicsLayer();
         m_rootLayer = pinchViewport.rootGraphicsLayer()->platformLayer();
         m_rootTransformLayer = pinchViewport.rootGraphicsLayer();
-        updateRootLayerTransform();
     } else {
         m_rootGraphicsLayer = nullptr;
         m_rootLayer = nullptr;
         m_rootTransformLayer = nullptr;
-        // This means that we're transitioning to a new page. Suppress
-        // commits until Blink generates invalidations so we don't
-        // attempt to paint too early in the next page load.
-        m_layerTreeView->setDeferCommits(true);
-    }
+    }
+
+    setIsAcceleratedCompositingActive(layer != 0);
+
+    updateRootLayerTransform();
 
     if (m_layerTreeView) {
         if (m_rootLayer) {
@@ -4175,8 +4178,6 @@
             // We register viewport layers here since there may not be a layer
             // tree view prior to this point.
             page()->frameHost().pinchViewport().registerLayersWithTreeView(m_layerTreeView);
-            if (m_pageOverlays)
-                m_pageOverlays->update();
         } else {
             m_layerTreeView->clearRootLayer();
             page()->frameHost().pinchViewport().clearLayersForTreeView(m_layerTreeView);
@@ -4193,9 +4194,10 @@
 
 void WebViewImpl::invalidateRect(const IntRect& rect)
 {
-    if (m_layerTreeView)
+    if (m_isAcceleratedCompositingActive) {
+        ASSERT(m_layerTreeView);
         updateLayerTreeViewport();
-    else if (m_client)
+    } else if (m_client)
         m_client->didInvalidateRect(rect);
 }
 
@@ -4260,6 +4262,58 @@
     // FIXME: only unittests, click to play, Android priting, and printing (for headers and footers)
     // make this assert necessary. We should make them not hit this code and then delete allowsBrokenNullLayerTreeView.
     ASSERT(m_layerTreeView || !m_client || m_client->allowsBrokenNullLayerTreeView());
+}
+
+void WebViewImpl::setIsAcceleratedCompositingActive(bool active)
+{
+    // In the middle of shutting down; don't try to spin back up a compositor.
+    // FIXME: compositing startup/shutdown should be refactored so that it
+    // turns on explicitly rather than lazily, which causes this awkwardness.
+    if (m_layerTreeViewClosed)
+        return;
+
+    ASSERT(!active || m_layerTreeView);
+    Platform::current()->histogramEnumeration("GPU.setIsAcceleratedCompositingActive", active * 2 + m_isAcceleratedCompositingActive, 4);
+
+    if (m_isAcceleratedCompositingActive == active)
+        return;
+
+    if (!m_client)
+        return;
+
+    if (!active) {
+        m_isAcceleratedCompositingActive = false;
+        if (!m_layerTreeViewCommitsDeferred) {
+            ASSERT(m_layerTreeView);
+            // This means that we're transitioning to a new page. Suppress commits until WebKit generates invalidations so
+            // we don't attempt to paint too early in the next page load.
+            m_layerTreeView->setDeferCommits(true);
+            m_layerTreeViewCommitsDeferred = true;
+        }
+    } else {
+        TRACE_EVENT0("blink", "WebViewImpl::setIsAcceleratedCompositingActive(true)");
+        m_layerTreeView->setRootLayer(*m_rootLayer);
+
+        bool visible = page()->visibilityState() == PageVisibilityStateVisible;
+        m_layerTreeView->setVisible(visible);
+        updateLayerTreeDeviceScaleFactor();
+        m_layerTreeView->setPageScaleFactorAndLimits(pageScaleFactor(), minimumPageScaleFactor(), maximumPageScaleFactor());
+        updateLayerTreeBackgroundColor();
+        m_layerTreeView->setHasTransparentBackground(isTransparent());
+        updateLayerTreeViewport();
+        m_isAcceleratedCompositingActive = true;
+        if (m_pageOverlays)
+            m_pageOverlays->update();
+        // FIXME: allow emulation, fps counter and continuous painting at the same time: crbug.com/299837.
+        m_layerTreeView->setShowFPSCounter(m_showFPSCounter && !m_devToolsEmulator->deviceEmulationEnabled());
+        m_layerTreeView->setShowPaintRects(m_showPaintRects);
+        m_layerTreeView->setShowDebugBorders(m_showDebugBorders);
+        m_layerTreeView->setContinuousPaintingEnabled(m_continuousPaintingEnabled && !m_devToolsEmulator->deviceEmulationEnabled());
+        m_layerTreeView->setShowScrollBottleneckRects(m_showScrollBottleneckRects);
+        m_layerTreeView->heuristicsForGpuRasterizationUpdated(m_matchesHeuristicsForGpuRasterization);
+    }
+    if (page() && page()->mainFrame()->isLocalFrame())
+        page()->deprecatedLocalMainFrame()->view()->setClipsRepaints(!m_isAcceleratedCompositingActive);
 }
 
 void WebViewImpl::updateMainFrameScrollPosition(const DoublePoint& scrollPosition, bool programmaticScroll)
@@ -4383,10 +4437,11 @@
 
 void WebViewImpl::setVisibilityState(WebPageVisibilityState visibilityState,
                                      bool isInitialState) {
+    if (!page())
+        return;
+
     ASSERT(visibilityState == WebPageVisibilityStateVisible || visibilityState == WebPageVisibilityStateHidden || visibilityState == WebPageVisibilityStatePrerender);
-
-    if (page())
-        m_page->setVisibilityState(static_cast<PageVisibilityState>(static_cast<int>(visibilityState)), isInitialState);
+    m_page->setVisibilityState(static_cast<PageVisibilityState>(static_cast<int>(visibilityState)), isInitialState);
 
     if (m_layerTreeView) {
         bool visible = visibilityState == WebPageVisibilityStateVisible;