commit 8c14ad2e43c2e7ae309ad337f691281090ad4b01
author Victor Costan <pwnall@chromium.org> Thu Dec 14 16:39:22 2017
committer Commit Bot <commit-bot@chromium.org> Thu Dec 14 16:39:22 2017
tree 7f387a8be5409fd056ba13fa3f1c3aa068b7b0d6
parent 8c324f67ae0d013beece31f8a2d4650b0db14601

Make BlinkCloneableMessage and BlinkTransferableMessage move-only.

The mojo typemaps for BlinkCloneableMessage and BlinkTransferableMessage
specify that the structs are move-only, so the code in the mojo bindings
uses std::move. However, since the structs declare a custom constructor
(the constructor is defaulted in the .cpp, but the compiler can't see
this from the .h), no move constructor or move-assignment is generated,
and the structs are copied rather than being moved.

The mismatch causes extra reference increments / decrements. When the
underlying type uses thread-safe reference counter (like
SerializedScriptValue does), increments and decrements use atomic
operations, which are not cheap on ARM.

This CL adds move constructors and move-assignment operators to
BlinkCloneableMessage to allow moving, and adds DISALLOW_COPY_AND_ASSIGN
to prevent accidental copying.

This CL also adds DISALLOW_COPY_AND_ASSIGN to the browser-side
structures corresponding to Blink{Cloneable,Transferable}Message, to
make it obvious that they are move-only.

Bug: 794791
Change-Id: Iffe8f1e65bf9ccc2cd98082c341c2bdc3246fa33
Reviewed-on: https://chromium-review.googlesource.com/826260
Commit-Queue: Jeremy Roman <jbroman@chromium.org>
Reviewed-by: Jeremy Roman <jbroman@chromium.org>
Reviewed-by: Marijn Kruisselbrink <mek@chromium.org>
Cr-Commit-Position: refs/heads/master@{#524085}