Close renderer SharedBitmap file descriptors immediately after mapping

content/child/child_shared_bitmap_manager.cc

Index: content/child/child_shared_bitmap_manager.cc
diff --git a/content/child/child_shared_bitmap_manager.cc b/content/child/child_shared_bitmap_manager.cc
index 9dc86bd679b50880c1c0cee97278f0b3d8e59c90..aa9f1f37ba6dd854418aab8be314b2ece5d091c4 100644
--- a/content/child/child_shared_bitmap_manager.cc
+++ b/content/child/child_shared_bitmap_manager.cc
@@ -55,7 +55,13 @@ ChildSharedBitmapManager::~ChildSharedBitmapManager() {}
 
 scoped_ptr<cc::SharedBitmap> ChildSharedBitmapManager::AllocateSharedBitmap(
     const gfx::Size& size) {
-  return AllocateSharedMemoryBitmap(size);
+  scoped_ptr<SharedMemoryBitmap> bitmap = AllocateSharedMemoryBitmap(size);
+#if defined(OS_POSIX)
+  // Close file descriptor to avoid running out.
+  if (bitmap)
+    bitmap->shared_memory()->Close();
+#endif
+  return bitmap.Pass();
 }
 
 scoped_ptr<SharedMemoryBitmap>