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the pattern of SwapBuffers, for example, GLRenderer always issues
SwapBuffers calls with a specific IPC message patterns, it should always
be SetLatencyInfo->AsyncFlush->Echo sequence.

Instead of posting a task to message loop, it could avoid the possibility
of being blocked by other channels, and make SwapBuffers executed as soon
as possible.

BUG=407529

Review URL: https://codereview.chromium.org/495313003

Cr-Commit-Position: refs/heads/master@{#292768}