cc: Redraw incomplete frames when new texture uploads finish

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 e6b9ac99e0d49ae673f001b56a4ce6ad514d74aa..85fa620bfea3bce3215975e30e213a39a03649b5 100644
--- a/cc/layer_tree_host_impl.cc
+++ b/cc/layer_tree_host_impl.cc
@@ -464,9 +464,6 @@ bool LayerTreeHostImpl::calculateRenderPasses(FrameData& frame)
     // in the future.
     bool drawFrame = true;
 
-    // Make sure we have the most recent info regarding which textures have been uploaded.
-    checkForCompletedSetPixels();
-
     LayerIteratorType end = LayerIteratorType::end(frame.renderSurfaceLayerList);
     for (LayerIteratorType it = LayerIteratorType::begin(frame.renderSurfaceLayerList); it != end; ++it) {
         RenderPass::Id targetRenderPassId = it.targetRenderSurfaceLayer()->renderSurface()->renderPassId();
@@ -714,6 +711,12 @@ void LayerTreeHostImpl::ScheduleManageTiles()
       m_client->setNeedsManageTilesOnImplThread();
 }
 
+void LayerTreeHostImpl::DidUploadVisibleHighResolutionTile()
+{
+    if (m_client)
+        m_client->setNeedsRedrawOnImplThread();

[nduca, 2013/01/16 04:09:47]

see now i dont get why this one does setNeedsRedraw but the other one does
setNeedsRedrawOnBlahBlahBlah

[brianderson, 2013/01/16 20:12:22]

In this case, we know we have a better frame to draw.  In the other case, we
don't know if we have a better frame to draw until the next vsync (so it
indicates we will need an eventual redraw instead of an immediate one).  The
scheduler uses this info to tick without necessarily drawing.

+}
+
 bool LayerTreeHostImpl::shouldClearRootRenderPass() const
 {
     return m_settings.shouldClearRootRenderPass;
@@ -837,7 +840,13 @@ bool LayerTreeHostImpl::swapBuffers()
     DCHECK(m_renderer);
 
     m_fpsCounter->markEndOfFrame();
-    return m_renderer->swapBuffers();
+    bool result = m_renderer->swapBuffers();
+
+    if (!activeTree()->AreVisibleResourcesReady()) {

[nduca, 2013/01/16 04:09:47]

I'm confused, why are we checking this again here?

[brianderson, 2013/01/16 20:12:22]

This checks if the active tree just drawn was incomplete (checkered or low-res).
 If it was incomplete it lets the proxy know that it needs to redraw when it can
draw a more complete frame.

Maybe a better name for setNeedsRedrawOnVisibleTextureUploadOnImplThread would
be setSwapUsedIncompleteTexturesOnImplThread.

+      m_client->setNeedsRedrawOnVisibleTextureUploadOnImplThread();
+    }
+
+    return result;
 }
 
 const gfx::Size& LayerTreeHostImpl::deviceViewportSize() const
@@ -906,6 +915,8 @@ void LayerTreeHostImpl::createPendingTree()
     m_client->onHasPendingTreeStateChanged(pendingTree());
 }
 
+// This function should not be called from within a draw, as it can trigger
+// as spurious draw if a new visible tile gets upload.
 void LayerTreeHostImpl::checkForCompletedSetPixels()
 {
     if (m_tileManager)
@@ -917,8 +928,6 @@ void LayerTreeHostImpl::activatePendingTreeIfNeeded()
     if (!pendingTree())
         return;
 
-    checkForCompletedSetPixels();
-
     // It's always fine to activate to an empty tree.  Otherwise, only
     // activate once all visible resources in pending tree are ready.
     if (activeTree()->RootLayer() &&