Use px for units in browser controls offsets in native code

This patch removes two back and forth unit conversions in Tab's java
code and then in the RenderWidgetHostImpl, making px the unit used
to describe browser controls offsets and height everywhere.

Bug: 882508
Change-Id: I2fba83f659021f7c448d5012a0b3c7b16a20671c
Commit-Queue: Matthew Jones <>
Reviewed-by: Bo <>
Reviewed-by: David Trainor <>
Cr-Commit-Position: refs/heads/master@{#623772}
4 files changed