Abstract out ThreadDebugger from V8PerIsolateData

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

Index: third_party/WebKit/Source/core/inspector/MainThreadDebugger.cpp
diff --git a/third_party/WebKit/Source/core/inspector/MainThreadDebugger.cpp b/third_party/WebKit/Source/core/inspector/MainThreadDebugger.cpp
index 202710978799862311e6cfe6f78058cc04584667..9b7263e4a5f1c6660cb8dbd822ae728edf555871 100644
--- a/third_party/WebKit/Source/core/inspector/MainThreadDebugger.cpp
+++ b/third_party/WebKit/Source/core/inspector/MainThreadDebugger.cpp
@@ -30,6 +30,7 @@
 
 #include "core/inspector/MainThreadDebugger.h"
 
+#include <memory>
 #include "bindings/core/v8/BindingSecurity.h"
 #include "bindings/core/v8/DOMWrapperWorld.h"
 #include "bindings/core/v8/ScriptController.h"
@@ -65,7 +66,6 @@
 #include "platform/UserGestureIndicator.h"
 #include "wtf/PtrUtil.h"
 #include "wtf/ThreadingPrimitives.h"
-#include <memory>
 
 namespace blink {
 
@@ -216,11 +216,11 @@ int MainThreadDebugger::contextGroupId(LocalFrame* frame) {
 }
 
 MainThreadDebugger* MainThreadDebugger::instance() {
-  ASSERT(isMainThread());
-  V8PerIsolateData* data =
-      V8PerIsolateData::from(V8PerIsolateData::mainThreadIsolate());
-  ASSERT(data->threadDebugger() && !data->threadDebugger()->isWorker());
-  return static_cast<MainThreadDebugger*>(data->threadDebugger());
+  CHECK(isMainThread());

[Yuki, 2017/02/15 10:00:40]

ASSERT corresponds to DCHECK.
Is this change intentional?

By the way, RELEASE_ASSERT corresponds to CHECK.

[adithyas, 2017/02/15 18:12:12]

Ah, my bad. Thanks!

+  ThreadDebugger* debugger =
+      ThreadDebugger::getThreadDebugger(V8PerIsolateData::mainThreadIsolate());
+  CHECK(debugger && !debugger->isWorker());

[Yuki, 2017/02/15 10:00:40]

Ditto.

+  return static_cast<MainThreadDebugger*>(debugger);
 }
 
 void MainThreadDebugger::interruptMainThreadAndRun(