Adding blink gc memory dump infrastructure for thread specific dumps.

Source/platform/heap/ThreadState.h

Index: Source/platform/heap/ThreadState.h
diff --git a/Source/platform/heap/ThreadState.h b/Source/platform/heap/ThreadState.h
index 459b8acd854aa0178a933f85b33cea1ea8f0e366..33098b08552201eaf11a4eafa2098d950a49b523 100644
--- a/Source/platform/heap/ThreadState.h
+++ b/Source/platform/heap/ThreadState.h
@@ -34,6 +34,7 @@
 #include "platform/PlatformExport.h"
 #include "platform/heap/AddressSanitizer.h"
 #include "platform/heap/ThreadingTraits.h"
+#include "public/platform/WebMemoryDumpProvider.h"
 #include "public/platform/WebThread.h"
 #include "wtf/Forward.h"
 #include "wtf/HashMap.h"
@@ -164,7 +165,7 @@ struct AgeCounts {
 typedef HashMap<String, AgeCounts> ClassAgeCountsMap;
 #endif
 
-class PLATFORM_EXPORT ThreadState {
+class PLATFORM_EXPORT ThreadState : public WebMemoryDumpProvider {
     WTF_MAKE_NONCOPYABLE(ThreadState);
 public:
     // When garbage collecting we need to know whether or not there
@@ -457,6 +458,9 @@ public:
     // Visit all persistents allocated on this thread.
     void visitPersistents(Visitor*);
 
+    void snapshotMemoryIfNecessary();
+    void snapshotMemory();
+
 #if ENABLE(GC_PROFILING)
     const GCInfo* findGCInfo(Address);
     static const GCInfo* findGCInfoFromAllThreads(Address);
@@ -609,6 +613,9 @@ public:
     void allocationPointAdjusted(int heapIndex);
     void promptlyFreed(size_t gcInfoIndex);
 
+    // WebMemoryDumpProvider implementation.
+    bool onMemoryDump(WebProcessMemoryDump*) override;
+
 private:
     ThreadState();
     ~ThreadState();
@@ -706,6 +713,8 @@ private:
 
     Vector<PageMemoryRegion*> m_allocatedRegionsSinceLastGC;
 
+    OwnPtr<WebProcessMemoryDump> m_lastProcessMemoryDump;
+
 #if ENABLE(GC_PROFILING)
     double m_nextFreeListSnapshotTime;
 #endif