Simple BlinkGC heap compaction.

third_party/WebKit/Source/platform/heap/BUILD.gn

Index: third_party/WebKit/Source/platform/heap/BUILD.gn
diff --git a/third_party/WebKit/Source/platform/heap/BUILD.gn b/third_party/WebKit/Source/platform/heap/BUILD.gn
index 74691b25f0d21d6cdeabba96e69657b10144c620..4fc88f7f470e0317410f2768d1e137e10b4a4c68 100644
--- a/third_party/WebKit/Source/platform/heap/BUILD.gn
+++ b/third_party/WebKit/Source/platform/heap/BUILD.gn
@@ -26,6 +26,8 @@ source_set("heap") {
     "Heap.h",
     "HeapAllocator.cpp",
     "HeapAllocator.h",
+    "HeapCompact.cpp",
+    "HeapCompact.h",
     "HeapPage.cpp",
     "HeapPage.h",
     "InlinedGlobalMarkingVisitor.h",
@@ -42,6 +44,8 @@ source_set("heap") {
     "SafePoint.cpp",
     "SafePoint.h",
     "SelfKeepAlive.h",
+    "SparseHeapBitmap.cpp",
+    "SparseHeapBitmap.h",
     "StackFrameDepth.cpp",
     "StackFrameDepth.h",
     "ThreadState.cpp",
@@ -76,6 +80,7 @@ source_set("heap") {
 test("blink_heap_unittests") {
   sources = [
     "BlinkGCMemoryDumpProviderTest.cpp",
+    "HeapCompactTest.cpp",
     "HeapTest.cpp",
     "PersistentTest.cpp",
     "RunAllTests.cpp",