Support counter graphs in Timeline based on trace events

Source/bindings/v8/V8GCController.cpp

 /*
  * Copyright (C) 2009 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 392 matching lines @@
         // to collect all garbage, you need to wait until the next event loop.
         // Regarding (2), it would be OK in practice to trigger only one GC per gcEpilogue, because
         // GCController.collectAll() forces 7 V8's GC.
         Heap::collectGarbage(ThreadState::HeapPointersOnStack);
 
         // Forces a precise GC at the end of the current event loop.
         Heap::setForcePreciseGCForTesting();
     }
 
     TRACE_EVENT_END1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline"), "GCEvent", "usedHeapSizeAfter", usedHeapSize(isolate));
-    TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline"), "UpdateCounters", "", InspectorUpdateCountersEvent::data());
+    TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline"), "UpdateCounters", "data", InspectorUpdateCountersEvent::data());
 }
 
 void V8GCController::minorGCEpilogue(v8::Isolate* isolate)
 {
     TRACE_EVENT_END0("v8", "minorGC");
     if (isMainThread())
         TRACE_EVENT_SET_NONCONST_SAMPLING_STATE(V8PerIsolateData::from(isolate)->previousSamplingState());
 }
 
 void V8GCController::majorGCEpilogue(v8::Isolate* isolate)
@@ skipping 22 matching lines @@
     static size_t lastUsageReportedToV8 = 0;
 
     size_t currentUsage = Partitions::currentDOMMemoryUsage();
     int64_t diff = static_cast<int64_t>(currentUsage) - static_cast<int64_t>(lastUsageReportedToV8);
     isolate->AdjustAmountOfExternalAllocatedMemory(diff);
 
     lastUsageReportedToV8 = currentUsage;
 }
 
 }  // namespace WebCore