Refactor InspectorWebPerfAgent: update lifecycle management to be per Local Frame root; replace hea…

third_party/WebKit/Source/core/timing/Performance.cpp

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  * Copyright (C) 2012 Intel Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 17 matching lines @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "core/timing/Performance.h"
 
 #include "bindings/core/v8/ScriptValue.h"
 #include "bindings/core/v8/V8ObjectBuilder.h"
 #include "core/dom/Document.h"
 #include "core/frame/LocalFrame.h"
-#include "core/inspector/InspectedFrames.h"
 #include "core/inspector/InspectorWebPerfAgent.h"
 #include "core/loader/DocumentLoader.h"
 #include "core/origin_trials/OriginTrials.h"
 #include "core/timing/PerformanceTiming.h"
 
 namespace blink {
 
 static double toTimeOrigin(LocalFrame* frame) {
   if (!frame)
     return 0.0;
 
   Document* document = frame->document();
   if (!document)
     return 0.0;
 
   DocumentLoader* loader = document->loader();
   if (!loader)
     return 0.0;
 
   return loader->timing().referenceMonotonicTime();
 }
 
 Performance::Performance(LocalFrame* frame)
-    : PerformanceBase(toTimeOrigin(frame)), DOMWindowProperty(frame) {}
+    : PerformanceBase(toTimeOrigin(frame)),
+      DOMWindowProperty(frame),
+      m_observingLongTasks(false) {}
 
-Performance::~Performance() {}
+Performance::~Performance() {
+  LocalFrame* localRoot = frame()->localFrameRoot();

[krasin1, 2016/11/02 20:06:14]

For the record, this broke UBSan bots:
https://build.chromium.org/p/chromium.fyi/builders/UBSanVptr%20Linux/builds/1452

The reason is that frame() can return NULL on destruction. What is the correct
fix here? Just quit from the destructor early?

[panickercorp, 2016/11/02 20:17:47]

Apologies!
Should that have run on presubmit?

I'll prepare a fix and send right away. Thanks!
(yes cannot assume frame is non-null)

+  if (m_observingLongTasks && localRoot) {
+    m_observingLongTasks = false;
+    localRoot->disableInspectorWebPerfAgent(this);
+  }
+}
 
 ExecutionContext* Performance::getExecutionContext() const {
   if (!frame())
     return nullptr;
   return frame()->document();
 }
 
 MemoryInfo* Performance::memory() {
   return MemoryInfo::create();
 }
 
 PerformanceNavigation* Performance::navigation() const {
   if (!m_navigation)
     m_navigation = PerformanceNavigation::create(frame());
 
   return m_navigation.get();
 }
 
 PerformanceTiming* Performance::timing() const {
   if (!m_timing)
     m_timing = PerformanceTiming::create(frame());
 
   return m_timing.get();
 }
 
 void Performance::updateLongTaskInstrumentation() {
-  if (hasObserverFor(PerformanceEntry::LongTask) && !m_longTaskInspectorAgent) {
-    if (!frame() || !frame()->document() ||
-        !OriginTrials::longTaskObserverEnabled(frame()->document()))
-      return;
-    m_longTaskInspectorAgent = new InspectorWebPerfAgent(frame());
-    m_longTaskInspectorAgent->enable();
-  } else if (!hasObserverFor(PerformanceEntry::LongTask) &&
-             m_longTaskInspectorAgent) {
-    m_longTaskInspectorAgent->disable();
-    m_longTaskInspectorAgent = nullptr;
+  DCHECK(frame());
+  if (!frame()->document() ||
+      !OriginTrials::longTaskObserverEnabled(frame()->document()))
+    return;
+  LocalFrame* localRoot = frame()->localFrameRoot();
+  DCHECK(localRoot);
+
+  if (!m_observingLongTasks && hasObserverFor(PerformanceEntry::LongTask)) {
+    m_observingLongTasks = true;
+    localRoot->enableInspectorWebPerfAgent(this);
+  } else if (m_observingLongTasks &&
+             !hasObserverFor(PerformanceEntry::LongTask)) {
+    m_observingLongTasks = false;
+    localRoot->disableInspectorWebPerfAgent(this);
   }
 }
 
 ScriptValue Performance::toJSONForBinding(ScriptState* scriptState) const {
   V8ObjectBuilder result(scriptState);
   result.add("timing", timing()->toJSONForBinding(scriptState));
   result.add("navigation", navigation()->toJSONForBinding(scriptState));
   return result.scriptValue();
 }
 
+bool Performance::observingLongTasks() {
+  return m_observingLongTasks;
+}
+
 DEFINE_TRACE(Performance) {
   visitor->trace(m_navigation);
   visitor->trace(m_timing);
-  visitor->trace(m_longTaskInspectorAgent);
   DOMWindowProperty::trace(visitor);
   PerformanceBase::trace(visitor);
 }
 
 }  // namespace blink