Add reporting of JS heap size limit to GetHeapStatistics.

I found it useful to know inside the heap profiler to avoid
crashes due to heap overflow.

Review URL: http://codereview.chromium.org/6111007

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6266 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

include/v8.h

@@ -2515,6 +2515,7 @@ class V8EXPORT HeapStatistics {
   size_t total_heap_size() { return total_heap_size_; }
   size_t total_heap_size_executable() { return total_heap_size_executable_; }
   size_t used_heap_size() { return used_heap_size_; }
+  size_t heap_size_limit() { return heap_size_limit_; }
 
  private:
   void set_total_heap_size(size_t size) { total_heap_size_ = size; }
@@ -2522,10 +2523,12 @@ class V8EXPORT HeapStatistics {
     total_heap_size_executable_ = size;
   }
   void set_used_heap_size(size_t size) { used_heap_size_ = size; }
+  void set_heap_size_limit(size_t size) { heap_size_limit_ = size; }
 
   size_t total_heap_size_;
   size_t total_heap_size_executable_;
   size_t used_heap_size_;
+  size_t heap_size_limit_;
 
   friend class V8;
 };

src/api.cc

@@ -3299,7 +3299,8 @@ bool v8::V8::Dispose() {
 
 HeapStatistics::HeapStatistics(): total_heap_size_(0),
                                   total_heap_size_executable_(0),
-                                  used_heap_size_(0) { }
+                                  used_heap_size_(0),
+                                  heap_size_limit_(0) { }
 
 
 void v8::V8::GetHeapStatistics(HeapStatistics* heap_statistics) {
@@ -3307,6 +3308,7 @@ void v8::V8::GetHeapStatistics(HeapStatistics* heap_statistics) {
   heap_statistics->set_total_heap_size_executable(
       i::Heap::CommittedMemoryExecutable());
   heap_statistics->set_used_heap_size(i::Heap::SizeOfObjects());
+  heap_statistics->set_heap_size_limit(i::Heap::MaxReserved());
 }