Revert "Optimize IMT"

This reverts commit 0790af1391b316c5c12b4e135be357008c060696.

Bug: 29188168 (for initial CL)
Bug: 29778499 (reason for revert)

Change-Id: I2c3e4ec2cebdd40faec67ddb721b7acdc8e90061
27 files changed