[profiler] Implement POC Sampling Heap Profiler

src/heap/spaces.h

Index: src/heap/spaces.h
diff --git a/src/heap/spaces.h b/src/heap/spaces.h
index 19708dcb782315ab9ce2974137db96e86bf0601a..0d924dc014e381a977f2c723607db94a01d4ae6d 100644
--- a/src/heap/spaces.h
+++ b/src/heap/spaces.h
@@ -20,6 +20,7 @@ namespace v8 {
 namespace internal {
 
 class CompactionSpaceCollection;
+class InlineAllocationObserver;
 class Isolate;
 
 // -----------------------------------------------------------------------------
@@ -2567,54 +2568,6 @@ class NewSpacePageIterator BASE_EMBEDDED {
   NewSpacePage* last_page_;
 };
 
-// -----------------------------------------------------------------------------
-// Allows observation of inline allocation in the new space.
-class InlineAllocationObserver {
- public:
-  explicit InlineAllocationObserver(intptr_t step_size)
-      : step_size_(step_size), bytes_to_next_step_(step_size) {
-    DCHECK(step_size >= kPointerSize);
-  }
-  virtual ~InlineAllocationObserver() {}
-
- private:
-  intptr_t step_size() const { return step_size_; }
-  intptr_t bytes_to_next_step() const { return bytes_to_next_step_; }
-
-  // Pure virtual method provided by the subclasses that gets called when at
-  // least step_size bytes have been allocated. soon_object is the address just
-  // allocated (but not yet initialized.) size is the size of the object as
-  // requested (i.e. w/o the alignment fillers). Some complexities to be aware
-  // of:
-  // 1) soon_object will be nullptr in cases where we end up observing an
-  //    allocation that happens to be a filler space (e.g. page boundaries.)
-  // 2) size is the requested size at the time of allocation. Right-trimming
-  //    may change the object size dynamically.
-  // 3) soon_object may actually be the first object in an allocation-folding
-  //    group. In such a case size is the size of the group rather than the
-  //    first object.
-  virtual void Step(int bytes_allocated, Address soon_object, size_t size) = 0;
-
-  // Called each time the new space does an inline allocation step. This may be
-  // more frequently than the step_size we are monitoring (e.g. when there are
-  // multiple observers, or when page or space boundary is encountered.)
-  void InlineAllocationStep(int bytes_allocated, Address soon_object,
-                            size_t size) {
-    bytes_to_next_step_ -= bytes_allocated;
-    if (bytes_to_next_step_ <= 0) {
-      Step(static_cast<int>(step_size_ - bytes_to_next_step_), soon_object,
-           size);
-      bytes_to_next_step_ = step_size_;
-    }
-  }
-
-  intptr_t step_size_;
-  intptr_t bytes_to_next_step_;
-
-  friend class NewSpace;
-
-  DISALLOW_COPY_AND_ASSIGN(InlineAllocationObserver);
-};
 
 // -----------------------------------------------------------------------------
 // The young generation space.