Don't try to access an Isolate when don't have one yet.

content/child/content_child_helpers.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/child/content_child_helpers.h"
 
 #if defined(OS_LINUX)
 #include <malloc.h>
 #endif
 
@@ skipping 11 matching lines @@
 #if defined(USE_TCMALLOC)
       minfo.uordblks
 #else
       (minfo.hblkhd + minfo.arena)
 #endif
       >> 10;
 
   v8::HeapStatistics stat;
   // TODO(svenpanne) The call below doesn't take web workers into account, this
   // has to be done manually by iterating over all Isolates involved.
-  v8::Isolate::GetCurrent()->GetHeapStatistics(&stat);
+  v8::Isolate* isolate = v8::Isolate::GetCurrent();
+  if (isolate)
+    isolate->GetHeapStatistics(&stat);
   return mem_usage + (static_cast<uint64_t>(stat.total_heap_size()) >> 10);
 }
 #elif defined(OS_MACOSX)
 size_t GetMemoryUsageKB() {
   scoped_ptr<base::ProcessMetrics> process_metrics(
       // The default port provider is sufficient to get data for the current
       // process.
       base::ProcessMetrics::CreateProcessMetrics(
           base::GetCurrentProcessHandle(), NULL));
   return process_metrics->GetWorkingSetSize() >> 10;
 }
 #else
 size_t GetMemoryUsageKB() {
   scoped_ptr<base::ProcessMetrics> process_metrics(
       base::ProcessMetrics::CreateProcessMetrics(
           base::GetCurrentProcessHandle()));
   return process_metrics->GetPagefileUsage() >> 10;
 }
 #endif
 
 }  // namespace content