Round the size of shared memory regions up to 64K. This allows

native client modules to map these regions.  With this fix,
Pepper audio works on all three platforms.

Review URL: http://codereview.chromium.org/1242006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@42621 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 8 insertions, 1 deletions

diff --git a/base/shared_memory_win.cc b/base/shared_memory_win.cc
index 4afad3a..7d3e4cd 100644
--- a/base/shared_memory_win.cc
+++ b/base/shared_memory_win.cc
@@ -65,10 +65,17 @@ bool SharedMemory::Create(const std::wstring &name, bool read_only,
                           bool open_existing, uint32 size) {
   DCHECK(mapped_file_ == NULL);
 
+  // NaCl's memory allocator requires 0mod64K alignment and size for
+  // shared memory objects.  To allow passing shared memory to NaCl,
+  // therefore we round the size actually created to the nearest 64K unit.
+  // To avoid client impact, we continue to retain the size as the
+  // actual requested size.
+  uint32 rounded_size = (size + 0xffff) & ~0xffff;
   name_ = name;
   read_only_ = read_only;
   mapped_file_ = CreateFileMapping(INVALID_HANDLE_VALUE, NULL,
-      read_only_ ? PAGE_READONLY : PAGE_READWRITE, 0, static_cast<DWORD>(size),
+      read_only_ ? PAGE_READONLY : PAGE_READWRITE, 0,
+      static_cast<DWORD>(rounded_size),
       name.empty() ? NULL : name.c_str());
   if (!mapped_file_)
     return false;