Add LayerTreeHostClient::{will,did}UpdateLayer, report layer updates to DevTools

content/renderer/render_view_impl.cc

Index: content/renderer/render_view_impl.cc
diff --git a/content/renderer/render_view_impl.cc b/content/renderer/render_view_impl.cc
index e55fb8a94b1fbe3c877de83315d94ef5f1f5af49..0526669a4dacaf9d2374f768bfe0a5d7a7ac29ea 100644
--- a/content/renderer/render_view_impl.cc
+++ b/content/renderer/render_view_impl.cc
@@ -917,7 +917,9 @@ void RenderViewImpl::Initialize(RenderViewImplParams* params) {
   // along with the RenderView automatically.
   devtools_agent_ = new DevToolsAgent(this);
   mouse_lock_dispatcher_ = new RenderViewMouseLockDispatcher(this);
-
+  if (RenderWidgetCompositor* rwc = compositor()) {
+    webview()->devToolsAgent()->setLayerTreeId(rwc->GetLayerTreeId());
+  }
   new ImageLoadingHelper(this);
 
   // Create renderer_accessibility_ if needed.
@@ -6331,6 +6333,14 @@ bool RenderViewImpl::AllowPartialSwap() const {
   return allow_partial_swap_;
 }
 
+void RenderViewImpl::initializeLayerTreeView() {
+  RenderWidget::initializeLayerTreeView();
+  RenderWidgetCompositor* rwc = compositor();
+  if (!rwc || !webview() || !webview()->devToolsAgent())
+    return;
+  webview()->devToolsAgent()->setLayerTreeId(rwc->GetLayerTreeId());
+}
+
 #if defined(OS_WIN)
 void RenderViewImpl::PluginFocusChanged(bool focused, int plugin_id) {
   if (focused)