Report DOM partitionAlloc size to V8 GC.

Source/bindings/v8/V8GCController.cpp

Index: Source/bindings/v8/V8GCController.cpp
diff --git a/Source/bindings/v8/V8GCController.cpp b/Source/bindings/v8/V8GCController.cpp
index 5af7b234619775b879b93a29707a24e302f1a738..0a37a1cdae5c5c15e94770c9f9741e089eda599a 100644
--- a/Source/bindings/v8/V8GCController.cpp
+++ b/Source/bindings/v8/V8GCController.cpp
@@ -48,6 +48,7 @@
 #include "core/html/HTMLTemplateElement.h"
 #include "core/inspector/InspectorTraceEvents.h"
 #include "core/svg/SVGElement.h"
+#include "platform/Partitions.h"
 #include "platform/TraceEvent.h"
 
 namespace WebCore {
@@ -319,6 +320,7 @@ void V8GCController::gcPrologue(v8::GCType type, v8::GCCallbackFlags flags)
     // FIXME: It would be nice if the GC callbacks passed the Isolate directly....
     v8::Isolate* isolate = v8::Isolate::GetCurrent();
     TRACE_EVENT_BEGIN1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline"), "GCEvent", "usedHeapSizeBefore", usedHeapSize(isolate));
+    reportDOMMemoryUsageToV8(isolate);
     if (type == v8::kGCTypeScavenge)
         minorGCPrologue(isolate);
     else if (type == v8::kGCTypeMarkSweepCompact)
@@ -417,4 +419,18 @@ void V8GCController::collectGarbage(v8::Isolate* isolate)
     V8ScriptRunner::compileAndRunInternalScript(v8String(isolate, "if (gc) gc();"), isolate);
 }
 
+void V8GCController::reportDOMMemoryUsageToV8(v8::Isolate* isolate)
+{
+    if (!isMainThread())

[jochen (gone - plz use gerrit), 2014/05/28 07:23:03]

why?

[kouhei (in TOK), 2014/05/28 07:35:20]

We only want to notify main thread isolate, as all DOM Node objects should be in
main thread.

+        return;
+
+    static size_t lastUsageReportedToV8 = 0;
+
+    size_t currentUsage = Partitions::currentDOMMemoryUsage();
+    ssize_t diff = static_cast<ssize_t>(currentUsage) - static_cast<ssize_t>(lastUsageReportedToV8);
+    isolate->AdjustAmountOfExternalAllocatedMemory(diff);
+
+    lastUsageReportedToV8 = currentUsage;
+}
+
 }  // namespace WebCore