Oilpan: Add a missing null check for Platform::current()

Source/platform/heap/ThreadState.cpp

 /*
  * Copyright (C) 2013 Google 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.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 645 matching lines @@
 {
     // Idle GC is supported only in the main thread.
     if (!isMainThread())
         return;
 
     if (isSweepingInProgress()) {
         setGCState(SweepingAndIdleGCScheduled);
         return;
     }
 
-    Platform::current()->currentThread()->scheduler()->postNonNestableIdleTask(FROM_HERE, WTF::bind<double>(&ThreadState::performIdleGC, this));
-    setGCState(IdleGCScheduled);
+    if (Platform::current()) {

[sof, 2015/04/23 18:22:41]

Platform::current() will exist, but it may not have a thread (cf.
initializeWithoutV8())

+        Platform::current()->currentThread()->scheduler()->postNonNestableIdleTask(FROM_HERE, WTF::bind<double>(&ThreadState::performIdleGC, this));
+        setGCState(IdleGCScheduled);
+    }
 }
 
 void ThreadState::scheduleIdleLazySweep()
 {
     // Idle complete sweep is supported only in the main thread.
     if (!isMainThread())
         return;
 
     // TODO(haraken): Remove this. Lazy sweeping is not yet enabled in non-oilpan builds.
 #if ENABLE(OILPAN)
-    Platform::current()->currentThread()->scheduler()->postIdleTask(FROM_HERE, WTF::bind<double>(&ThreadState::performIdleLazySweep, this));
+    if (Platform::current()) {
+        Platform::current()->currentThread()->scheduler()->postIdleTask(FROM_HERE, WTF::bind<double>(&ThreadState::performIdleLazySweep, this));
+    }
 #endif
 }
 
 void ThreadState::schedulePreciseGC()
 {
     if (isSweepingInProgress()) {
         setGCState(SweepingAndPreciseGCScheduled);
         return;
     }
 
@@ skipping 607 matching lines @@
         json->beginArray(it->key.ascii().data());
         for (size_t age = 0; age <= maxHeapObjectAge; ++age)
             json->pushInteger(it->value.ages[age]);
         json->endArray();
     }
     TRACE_EVENT_OBJECT_SNAPSHOT_WITH_ID(TRACE_DISABLED_BY_DEFAULT("blink_gc"), statsName, this, json.release());
 }
 #endif
 
 } // namespace blink