[DevTools] avoid async task id collisions

V8 internally uses odd numbers as task id, blink should always send
even numbers only.
This CL fixes ids for network related async tasks.

R=pfeldman@chromium.org

Bug: none
Change-Id: I44a68b65f5992066bca4fb8a69566db66feaf143
Reviewed-on: https://chromium-review.googlesource.com/764514Reviewed-by: Pavel Feldman <pfeldman@chromium.org>
Commit-Queue: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#515807}

third_party/WebKit/Source/core/inspector/InspectorTraceEvents.cpp

@@ -50,6 +50,7 @@ namespace blink {
 namespace {
 
 void* AsyncId(unsigned long identifier) {
+  // This value should be odd to avoid collisions with regular pointers.
   return reinterpret_cast<void*>((identifier << 1) | 1);
 }
 

third_party/WebKit/Source/core/inspector/ThreadDebugger.cpp

@@ -82,11 +82,13 @@ void ThreadDebugger::IdleFinished(v8::Isolate* isolate) {
 void ThreadDebugger::AsyncTaskScheduled(const String& operation_name,
                                         void* task,
                                         bool recurring) {
+  DCHECK_EQ(reinterpret_cast<intptr_t>(task) % 2, 0);
   v8_inspector_->asyncTaskScheduled(ToV8InspectorStringView(operation_name),
                                     task, recurring);
 }
 
 void ThreadDebugger::AsyncTaskCanceled(void* task) {
+  DCHECK_EQ(reinterpret_cast<intptr_t>(task) % 2, 0);
   v8_inspector_->asyncTaskCanceled(task);
 }
 
@@ -95,10 +97,12 @@ void ThreadDebugger::AllAsyncTasksCanceled() {
 }
 
 void ThreadDebugger::AsyncTaskStarted(void* task) {
+  DCHECK_EQ(reinterpret_cast<intptr_t>(task) % 2, 0);
   v8_inspector_->asyncTaskStarted(task);
 }
 
 void ThreadDebugger::AsyncTaskFinished(void* task) {
+  DCHECK_EQ(reinterpret_cast<intptr_t>(task) % 2, 0);
   v8_inspector_->asyncTaskFinished(task);
 }
 

third_party/WebKit/Source/core/probe/CoreProbes.cpp

@@ -50,12 +50,21 @@
 namespace blink {
 namespace probe {
 
+namespace {
+void* AsyncId(void* task) {
+  // Blink uses odd ids for network requests and even ids for everything else.
+  // We should make all of them even before reporting to V8 to avoid collisions
+  // with internal V8 async events.
+  return reinterpret_cast<void*>(reinterpret_cast<intptr_t>(task) << 1);
+}
+}  // namespace
+
 AsyncTask::AsyncTask(ExecutionContext* context,
                      void* task,
                      const char* step,
                      bool enabled)
     : debugger_(enabled ? ThreadDebugger::From(ToIsolate(context)) : nullptr),
-      task_(task),
+      task_(AsyncId(task)),
       recurring_(step) {
   if (recurring_) {
     TRACE_EVENT_FLOW_STEP0("devtools.timeline.async", "AsyncTask",
@@ -84,7 +93,7 @@ void AsyncTaskScheduled(ExecutionContext* context,
                           TRACE_ID_LOCAL(reinterpret_cast<uintptr_t>(task)),
                           "data", InspectorAsyncTask::Data(name));
   if (ThreadDebugger* debugger = ThreadDebugger::From(ToIsolate(context)))
-    debugger->AsyncTaskScheduled(name, task, true);
+    debugger->AsyncTaskScheduled(name, AsyncId(task), true);
 }
 
 void AsyncTaskScheduledBreakable(ExecutionContext* context,
@@ -96,7 +105,7 @@ void AsyncTaskScheduledBreakable(ExecutionContext* context,
 
 void AsyncTaskCanceled(ExecutionContext* context, void* task) {
   if (ThreadDebugger* debugger = ThreadDebugger::From(ToIsolate(context)))
-    debugger->AsyncTaskCanceled(task);
+    debugger->AsyncTaskCanceled(AsyncId(task));
   TRACE_EVENT_FLOW_END0("devtools.timeline.async", "AsyncTask",
                         TRACE_ID_LOCAL(reinterpret_cast<uintptr_t>(task)));
 }