Adding V8 api to get memory statistics of spaces in V8::Heap.

include/v8.h

Index: include/v8.h
diff --git a/include/v8.h b/include/v8.h
index cdb23b4655d6b2caadde4a9bd16f45d99902e4fd..572b2f9fc1ab5c7a938e43e5df8cd4503402db9b 100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -4895,6 +4895,26 @@ class V8_EXPORT HeapStatistics {
 };
 
 
+class HeapSpaceStatistics {
+ public:
+  HeapSpaceStatistics();
+  const char* space_name() { return space_name_; }
+  size_t space_size() { return space_size_;}
+  size_t space_used_size() { return space_used_size_; }
+  size_t space_avalable_size() { return space_avalable_size_; }
+  size_t physical_space_size() { return physical_space_size_; }
+
+ private:
+  const char* space_name_;
+  size_t space_size_;
+  size_t space_used_size_;
+  size_t space_avalable_size_;
+  size_t physical_space_size_;
+
+  friend class Isolate;
+};
+
+
 class RetainedObjectInfo;
 
 
@@ -5257,6 +5277,21 @@ class V8_EXPORT Isolate {
   void GetHeapStatistics(HeapStatistics* heap_statistics);
 
   /**
+   * Returns the number of spaces in the heap.
+   */
+  int NumberOfHeapSpaces();
+
+  /**
+   * Get the memory usage of a space in the heap.
+   *
+   * \param space_statistics the HeapSpaceStatistics object to fill in
+   *   statistics.
+   * \param index ranges from 0 - number of spaces in the heap (given by
+   *   NumberOfHeapSpaces()).
+   */
+  void GetHeapSpaceStatistics(HeapSpaceStatistics* space_statistics, int index);

[rmcilroy, 2015/04/15 10:21:42]

return a bool to inform caller of success or failure (e.g., space_statistics
being NULL or index out of range).

[ssid, 2015/04/15 10:43:57]

Done.

+
+  /**
    * Get a call stack sample from the isolate.
    * \param state Execution state.
    * \param frames Caller allocated buffer to store stack frames.