Make VEA test support videos with different coded size and visible size

base/files/memory_mapped_file_posix.cc

Index: base/files/memory_mapped_file_posix.cc
diff --git a/base/files/memory_mapped_file_posix.cc b/base/files/memory_mapped_file_posix.cc
index ebf38779f039708835242eb19ed7223927a28f40..3010daac9605aebac42f74ae296c13e0bc4339c1 100644
--- a/base/files/memory_mapped_file_posix.cc
+++ b/base/files/memory_mapped_file_posix.cc
@@ -60,9 +60,13 @@ bool MemoryMappedFile::MapFileRegionToMemory(
     length_ = static_cast<size_t>(region.size);
   }
 
+  int flags = PROT_READ;

[rvargas (doing something else), 2014/08/27 18:24:25]

I'm sorry, but you are still trying to make this automagically without callers
being fully aware of what they are doing.

If a caller wants to create a mapped section with write access, MemoryMappedFile
should have a clear API to explicitly allow that behavior. Either an argument
somewhere should specify the desired access, or some new method should declare
that intent.

Note that passing a file with read/write access is not an indication that the
mapped memory should also have read/write access. If a caller passes a file with
read only access and asks MemoryMappedFile for write access, we should let the
OS reject the operation (there is no reliable way to go back to File::Flags from
a File)

+  if (file_.flags() & File::FLAG_WRITE ||
+      file_.flags() & File::FLAG_APPEND)
+    flags |= PROT_WRITE;
   data_ = static_cast<uint8*>(mmap(NULL,
                                    map_size,
-                                   PROT_READ,
+                                   flags,
                                    MAP_SHARED,
                                    file_.GetPlatformFile(),
                                    map_start));