Write access to the shared memory region is required because JavaScript lacks
the capability to create read-only ArrayBuffers. When a user attempts to modify
an ArrayBuffer that utilizes a ReadOnlySharedMemoryRegion as its BackingStore
it triggers an access violation.
Note that this pull request may be reverted in the future if JavaScript adds
read-only ArrayBuffer support.
CefSharedProcessMessageBuilder supports creation of a CefProcessMessage
backed by a CefSharedMemoryRegion.
Performance tests comparing the existing ArgumentList approach and the new
SharedMemoryRegion approach have been added to cefclient at
http://tests/ipc_performance.
CefMessageRouter has been updated to use SharedMemoryRegion as transport
for larger message payloads. The threshold is configurable via
|CefMessageRouterConfig.message_size_threshold|.
To test:
run `ceftests --gtest_filter=SendSharedProcessMessageTest.*:SharedProcessMessageTest.*:MessageRouterTest.Threshold*`
