[cc] Add tracing for tree activation state

R=reveman
BUG=172139
NOTRY=True

Review URL: https://chromiumcodereview.appspot.com/12095008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@179136 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 25 insertions, 0 deletions

diff --git a/cc/layer_tree_host_impl.cc b/cc/layer_tree_host_impl.cc
index 37ae8f4..42aa953 100644
--- a/cc/layer_tree_host_impl.cc
+++ b/cc/layer_tree_host_impl.cc
@@ -920,6 +920,7 @@ void LayerTreeHostImpl::createPendingTree()
         m_pendingTree = LayerTreeImpl::create(this);
     m_client->onCanDrawStateChanged(canDraw());
     m_client->onHasPendingTreeStateChanged(pendingTree());
+    TRACE_EVENT_ASYNC_BEGIN0("cc", "PendingTree", m_pendingTree.get());
 }
 
 void LayerTreeHostImpl::checkForCompletedTileUploads()
@@ -929,6 +930,25 @@ void LayerTreeHostImpl::checkForCompletedTileUploads()
         m_tileManager->CheckForCompletedTileUploads();
 }
 
+scoped_ptr<base::Value> LayerTreeHostImpl::activationStateAsValue() const
+{
+    scoped_ptr<base::DictionaryValue> state(new base::DictionaryValue());
+    state->SetBoolean("visible_resources_ready", pendingTree()->AreVisibleResourcesReady());
+    state->Set("tile_manager", m_tileManager->AsValue().release());
+    return state.PassAs<base::Value>();
+}
+
+namespace {
+
+std::string ValueToString(scoped_ptr<base::Value> value)
+{
+    std::string str;
+    base::JSONWriter::Write(value.get(), &str);
+    return str;
+}
+
+}
+
 void LayerTreeHostImpl::activatePendingTreeIfNeeded()
 {
     if (!pendingTree())
@@ -938,6 +958,10 @@ void LayerTreeHostImpl::activatePendingTreeIfNeeded()
 
     pendingTree()->UpdateDrawProperties(LayerTreeImpl::UPDATE_PENDING_TREE);
 
+    TRACE_EVENT_ASYNC_STEP1("cc",
+                            "PendingTree", m_pendingTree.get(), "activate",
+                            "state", ValueToString(activationStateAsValue()));
+
     // It's always fine to activate to an empty tree.  Otherwise, only
     // activate once all visible resources in pending tree are ready
     // or tile manager has no work scheduled for pending tree.
@@ -952,6 +976,7 @@ void LayerTreeHostImpl::activatePendingTreeIfNeeded()
 void LayerTreeHostImpl::activatePendingTree()
 {
     CHECK(m_pendingTree);
+    TRACE_EVENT_ASYNC_END0("cc", "PendingTree", m_pendingTree.get());
 
     m_activeTree->PushPersistedState(m_pendingTree.get());
     m_activeTree->SetRootLayer(TreeSynchronizer::synchronizeTrees(m_pendingTree->RootLayer(), m_activeTree->DetachLayerTree(), m_activeTree.get()));