cc: Split out calcDrawEtc from drawLayers

cc/layer_tree_host_impl.cc

Index: cc/layer_tree_host_impl.cc
diff --git a/cc/layer_tree_host_impl.cc b/cc/layer_tree_host_impl.cc
index a3a0f9ad981f777bcd5fabedf08549fa8f2bea95..ce8b29d872689a26d117e68fe910047b0b9db0f3 100644
--- a/cc/layer_tree_host_impl.cc
+++ b/cc/layer_tree_host_impl.cc
@@ -221,6 +221,7 @@ LayerTreeHostImpl::LayerTreeHostImpl(const LayerTreeSettings& settings, LayerTre
     , m_backgroundColor(0)
     , m_hasTransparentBackground(false)
     , m_needsAnimateLayers(false)
+    , m_needsUpdateLayers(false)
     , m_pinchGestureActive(false)
     , m_fpsCounter(FrameRateCounter::create(m_proxy->hasImplThread()))
     , m_debugRectHistory(DebugRectHistory::create())
@@ -248,6 +249,14 @@ void LayerTreeHostImpl::beginCommit()
 void LayerTreeHostImpl::commitComplete()
 {
     TRACE_EVENT0("cc", "LayerTreeHostImpl::commitComplete");
+
+    // Impl-side painting needs an update immediately post-commit to have the
+    // opportunity to create tilings.  Other paths can call updateLayers
+    // more lazily when needed prior to drawing.
+    setNeedsUpdateLayers();
+    if (m_settings.implSidePainting)
+        updateLayers();
+
     // Recompute max scroll position; must be after layer content bounds are
     // updated.
     updateMaxScrollOffset();
@@ -325,6 +334,7 @@ void LayerTreeHostImpl::startPageScaleAnimation(gfx::Vector2d targetOffset, bool
         m_pageScaleAnimation->zoomTo(scaledTargetOffset, pageScale, duration.InSecondsF());
     }
 
+    setNeedsUpdateLayers();
     m_client->setNeedsRedrawOnImplThread();
     m_client->setNeedsCommitOnImplThread();
 }
@@ -367,15 +377,29 @@ void LayerTreeHostImpl::updateRootScrollLayerImplTransform()
 {
     if (m_rootScrollLayerImpl) {
         m_rootScrollLayerImpl->setImplTransform(implTransform());
+        setNeedsUpdateLayers();

[danakj, 2012/12/06 03:23:04]

The layer will do this.

     }
 }
 
+void LayerTreeHostImpl::updateLayers()
+{
+    if (!needsUpdateLayers())

[danakj, 2012/12/06 03:23:04]

m_

[enne (OOO), 2012/12/06 17:20:23]

Why?

[danakj, 2012/12/06 17:38:50]

Cuz we always generally do this. Less indirection/uncertainty about what's being
read.

+        return;
+
+    m_renderSurfaceLayerList.clear();
+    m_needsUpdateLayers = false;
+
+    if (!m_rootLayerImpl)
+        return;
+
+    calculateRenderSurfaceLayerList(m_renderSurfaceLayerList);
+}
+
 void LayerTreeHostImpl::calculateRenderSurfaceLayerList(LayerList& renderSurfaceLayerList)
 {
     DCHECK(renderSurfaceLayerList.empty());
     DCHECK(m_rootLayerImpl);
     DCHECK(m_renderer); // For maxTextureSize.
-
     {
         updateRootScrollLayerImplTransform();
 
@@ -383,7 +407,6 @@ void LayerTreeHostImpl::calculateRenderSurfaceLayerList(LayerList& renderSurface
         float pageScaleFactor = m_pinchZoomViewport.pageScaleFactor();
         LayerTreeHostCommon::calculateDrawProperties(m_rootLayerImpl.get(), deviceViewportSize(), m_deviceScaleFactor, pageScaleFactor, &m_layerSorter, rendererCapabilities().maxTextureSize, renderSurfaceLayerList);
 
-        trackDamageForAllSurfaces(m_rootLayerImpl.get(), renderSurfaceLayerList);
     }
 }
 
@@ -482,8 +505,10 @@ static void appendQuadsToFillScreen(RenderPass* targetRenderPass, LayerImpl* roo
 bool LayerTreeHostImpl::calculateRenderPasses(FrameData& frame)
 {
     DCHECK(frame.renderPasses.empty());
+    if (!m_rootLayerImpl)

[danakj, 2012/12/06 03:23:04]

This is DCHECKed in prepareToDraw, by asking canDraw()

+        return false;
 
-    calculateRenderSurfaceLayerList(*frame.renderSurfaceLayerList);
+    trackDamageForAllSurfaces(m_rootLayerImpl.get(), *frame.renderSurfaceLayerList);
 
     TRACE_EVENT1("cc", "LayerTreeHostImpl::calculateRenderPasses", "renderSurfaceLayerList.size()", static_cast<long long unsigned>(frame.renderSurfaceLayerList->size()));
 
@@ -529,6 +554,7 @@ bool LayerTreeHostImpl::calculateRenderPasses(FrameData& frame)
             if (occlusionTracker.occluded(it->renderTarget(), it->visibleContentRect(), it->drawTransform(), implDrawTransformIsUnknown, it->drawableContentRect(), &hasOcclusionFromOutsideTargetSurface))
                 appendQuadsData.hadOcclusionFromOutsideTargetSurface |= hasOcclusionFromOutsideTargetSurface;
             else {
+                DCHECK(it->layerTreeHostImpl());
                 it->willDraw(m_resourceProvider.get());
                 frame.willDrawLayers.push_back(*it);
 
@@ -737,10 +763,10 @@ bool LayerTreeHostImpl::prepareToDraw(FrameData& frame)
     TRACE_EVENT0("cc", "LayerTreeHostImpl::prepareToDraw");
     DCHECK(canDraw());
 
+    updateLayers();
     frame.renderSurfaceLayerList = &m_renderSurfaceLayerList;
     frame.renderPasses.clear();
     frame.renderPassesById.clear();
-    frame.renderSurfaceLayerList->clear();
     frame.willDrawLayers.clear();
 
     if (!calculateRenderPasses(frame))
@@ -946,6 +972,7 @@ void LayerTreeHostImpl::setRootLayer(scoped_ptr<LayerImpl> layer)
     m_rootLayerImpl = layer.Pass();
     m_rootScrollLayerImpl = findRootScrollLayer(m_rootLayerImpl.get());
     m_currentlyScrollingLayerImpl = 0;
+    setNeedsUpdateLayers();
 
     if (m_rootLayerImpl && m_scrollingLayerIdFromPreviousTree != -1)
         m_currentlyScrollingLayerImpl = LayerTreeHostCommon::findLayerInSubtree(m_rootLayerImpl.get(), m_scrollingLayerIdFromPreviousTree);
@@ -961,6 +988,7 @@ scoped_ptr<LayerImpl> LayerTreeHostImpl::detachLayerTree()
     m_scrollingLayerIdFromPreviousTree = m_currentlyScrollingLayerImpl ? m_currentlyScrollingLayerImpl->id() : -1;
     m_currentlyScrollingLayerImpl = 0;
     m_renderSurfaceLayerList.clear();
+    setNeedsUpdateLayers();
 
     return m_rootLayerImpl.Pass();
 }
@@ -1095,9 +1123,8 @@ void LayerTreeHostImpl::setPageScaleFactorAndLimits(float pageScaleFactor, float
     float pageScaleChange = pageScaleFactor / m_pinchZoomViewport.pageScaleFactor();
     m_pinchZoomViewport.setPageScaleFactorAndLimits(pageScaleFactor, minPageScaleFactor, maxPageScaleFactor);
 
-    if (!m_settings.pageScalePinchZoomEnabled) {
-        if (pageScaleChange != 1)
-            adjustScrollsForPageScaleChange(m_rootScrollLayerImpl, pageScaleChange);
+    if (!m_settings.pageScalePinchZoomEnabled && pageScaleChange != 1) {
+        adjustScrollsForPageScaleChange(m_rootScrollLayerImpl, pageScaleChange);
     }
 
     // Clamp delta to limits and refresh display matrix.
@@ -1166,8 +1193,7 @@ bool LayerTreeHostImpl::ensureRenderSurfaceLayerList()
     // If we are called after setRootLayer() but before prepareToDraw(), we need
     // to recalculate the visible layers. This prevents being unable to scroll
     // during part of a commit.
-    m_renderSurfaceLayerList.clear();
-    calculateRenderSurfaceLayerList(m_renderSurfaceLayerList);
+    updateLayers();
 
     return m_renderSurfaceLayerList.size();
 }
@@ -1220,6 +1246,7 @@ InputHandlerClient::ScrollStatus LayerTreeHostImpl::scrollBegin(gfx::Point viewp
         // events are already in local layer coordinates so we can just apply them directly.
         m_scrollDeltaIsInViewportSpace = (type == Gesture);
         m_numImplThreadScrolls++;
+        setNeedsUpdateLayers();
         return ScrollStarted;
     }
     return ScrollIgnored;
@@ -1332,6 +1359,7 @@ bool LayerTreeHostImpl::scrollBy(const gfx::Point& viewportPoint,
     if (didScroll) {
         m_client->setNeedsCommitOnImplThread();
         m_client->setNeedsRedrawOnImplThread();
+        setNeedsUpdateLayers();
     }
     return didScroll;
 }
@@ -1387,6 +1415,7 @@ void LayerTreeHostImpl::pinchGestureUpdate(float magnifyDelta, gfx::Point anchor
 
     m_client->setNeedsCommitOnImplThread();
     m_client->setNeedsRedrawOnImplThread();
+    setNeedsUpdateLayers();
 }
 
 void LayerTreeHostImpl::pinchGestureEnd()
@@ -1523,6 +1552,7 @@ void LayerTreeHostImpl::animatePageScale(base::TimeTicks time)
         nextScroll.Scale(m_pinchZoomViewport.pageScaleFactor());
     m_rootScrollLayerImpl->scrollBy(nextScroll - scrollTotal);
     m_client->setNeedsRedrawOnImplThread();
+    setNeedsUpdateLayers();
 
     if (m_pageScaleAnimation->isAnimationCompleteAtTime(monotonicTime)) {
         m_pageScaleAnimation.reset();
@@ -1545,8 +1575,10 @@ void LayerTreeHostImpl::animateLayers(base::TimeTicks monotonicTime, base::Time
     if (!events->empty())
         m_client->postAnimationEventsToMainThreadOnImplThread(events.Pass(), wallClockTime);
 
-    if (didAnimate)
+    if (didAnimate) {
         m_client->setNeedsRedrawOnImplThread();
+        setNeedsUpdateLayers();
+    }
 
     setBackgroundTickingEnabled(!m_visible && m_needsAnimateLayers);
 }
@@ -1580,6 +1612,7 @@ void LayerTreeHostImpl::clearRenderSurfaces()
 {
     clearRenderSurfacesOnLayerImplRecursive(m_rootLayerImpl.get());
     m_renderSurfaceLayerList.clear();
+    setNeedsUpdateLayers();
 }
 
 std::string LayerTreeHostImpl::layerTreeAsText() const