Propagate failures from VirtualMemory::Commit.

runtime/vm/virtual_memory.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_VIRTUAL_MEMORY_H_
 #define VM_VIRTUAL_MEMORY_H_
 
 #include "platform/utils.h"
 #include "vm/globals.h"
 #include "vm/memory_region.h"
@@ skipping 17 matching lines @@
   uword end() const { return region_.end(); }
   void* address() const { return region_.pointer(); }
   intptr_t size() const { return region_.size(); }
 
   static void InitOnce();
 
   bool Contains(uword addr) const {
     return region_.Contains(addr);
   }
 
-  // Commits the virtual memory area, which is guaranteed to be zeroed.
+  // Commits the virtual memory area, which is guaranteed to be zeroed. Returns
+  // true on success and false on failure (e.g., out-of-memory).
   bool Commit(bool is_executable) {
     return Commit(start(), size(), is_executable);
   }
 
   // Changes the protection of the virtual memory area.
   static bool Protect(void* address, intptr_t size, Protection mode);
   bool Protect(Protection mode) {
     return Protect(address(), size(), mode);
   }
 
@@ skipping 39 matching lines @@
   intptr_t reserved_size_;
 
   static uword page_size_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(VirtualMemory);
 };
 
 }  // namespace dart
 
 #endif  // VM_VIRTUAL_MEMORY_H_