[PM] Implement a data describer for PageLoadTrackerDecorator.

Bug: 1068233
Change-Id: I31999fdfdada0061ca3bd274eded98a858ca1c4a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2137515
Commit-Queue: Sigurður Ásgeirsson <siggi@chromium.org>
Reviewed-by: François Doray <fdoray@chromium.org>
Cr-Commit-Position: refs/heads/master@{#757856}

components/performance_manager/decorators/page_load_tracker_decorator.cc

@@ -11,6 +11,7 @@
 #include "components/performance_manager/graph/node_attached_data_impl.h"
 #include "components/performance_manager/graph/page_node_impl.h"
 #include "components/performance_manager/graph/process_node_impl.h"
+#include "components/performance_manager/public/graph/node_data_describer_registry.h"
 
 namespace performance_manager {
 
@@ -45,6 +46,24 @@ class DataImpl : public PageLoadTrackerDecorator::Data,
   DISALLOW_COPY_AND_ASSIGN(DataImpl);
 };
 
+// static
+const char* ToString(LoadIdleState state) {
+  switch (state) {
+    case LoadIdleState::kLoadingNotStarted:
+      return "kLoadingNotStarted";
+    case LoadIdleState::kLoading:
+      return "kLoading";
+    case LoadIdleState::kLoadedNotIdling:
+      return "kLoadedNotIdling";
+    case LoadIdleState::kLoadedAndIdling:
+      return "kLoadedAndIdling";
+    case LoadIdleState::kLoadedAndIdle:
+      return "kLoadedAndIdle";
+  }
+}
+
+const char kDescriberName[] = "PageLoadTrackerDecorator";
+
 }  // namespace
 
 // static
@@ -67,12 +86,30 @@ void PageLoadTrackerDecorator::OnNetworkAlmostIdleChanged(
 
 void PageLoadTrackerDecorator::OnPassedToGraph(Graph* graph) {
   RegisterObservers(graph);
+  graph->GetNodeDataDescriberRegistry()->RegisterDescriber(this,
+                                                           kDescriberName);
 }
 
 void PageLoadTrackerDecorator::OnTakenFromGraph(Graph* graph) {
+  graph->GetNodeDataDescriberRegistry()->UnregisterDescriber(this);
   UnregisterObservers(graph);
 }
 
+base::Value PageLoadTrackerDecorator::DescribePageNodeData(
+    const PageNode* page_node) const {
+  auto* data = DataImpl::Get(PageNodeImpl::FromNode(page_node));
+  if (data == nullptr)
+    return base::Value();
+
+  base::Value ret(base::Value::Type::DICTIONARY);
+  ret.SetKey("load_idle_state_",
+             base::Value(ToString(data->load_idle_state())));
+  ret.SetKey("loading_received_response_",
+             base::Value(data->loading_received_response_));
+
+  return ret;
+}
+
 void PageLoadTrackerDecorator::OnMainThreadTaskLoadIsLow(
     const ProcessNode* process_node) {
   UpdateLoadIdleStateProcess(ProcessNodeImpl::FromNode(process_node));

components/performance_manager/decorators/page_load_tracker_decorator.h

@@ -9,6 +9,7 @@
 #include "base/timer/timer.h"
 #include "components/performance_manager/public/graph/frame_node.h"
 #include "components/performance_manager/public/graph/graph.h"
+#include "components/performance_manager/public/graph/node_data_describer.h"
 #include "components/performance_manager/public/graph/page_node.h"
 #include "components/performance_manager/public/graph/process_node.h"
 
@@ -25,6 +26,7 @@ class ProcessNodeImpl;
 // absolute timeout. This state is then updated on PageNodes in a graph.
 class PageLoadTrackerDecorator : public FrameNode::ObserverDefaultImpl,
                                  public GraphOwnedDefaultImpl,
+                                 public NodeDataDescriberDefaultImpl,
                                  public ProcessNode::ObserverDefaultImpl {
  public:
   class Data;
@@ -39,6 +41,9 @@ class PageLoadTrackerDecorator : public FrameNode::ObserverDefaultImpl,
   void OnPassedToGraph(Graph* graph) override;
   void OnTakenFromGraph(Graph* graph) override;
 
+  // NodeDataDescriber implementation:
+  base::Value DescribePageNodeData(const PageNode* node) const override;
+
   // ProcessNodeObserver implementation:
   void OnMainThreadTaskLoadIsLow(const ProcessNode* process_node) override;