Reland "Avoid copying Lengths (non-layout uses)"

This reverts commit ae5e5a5785d23ad6ca824b1ff399fe31b9060b77.

Reason for revert: The cause for the link failure is unknown but not the fault of the CL. (See for example https://crbug.com/921967 for similar failures.)

Original change's description:
> Revert "Avoid copying Lengths (non-layout uses)"
> 
> This reverts commit 784f852591a08f9bce6005cbb1df682cc5608af0.
> 
> Reason for revert: Causes link failures on Android FYI Release (Nexus 6P)
> 
> Original change's description:
> > Avoid copying Lengths (non-layout uses)
> > 
> > Copying/assigning a Length is not just a trivial copy, so when possible,
> > use a const Length& to avoid making a copy (saving some small bit of
> > footprint and hopefully a few CPU cycles too).
> > 
> > Change-Id: I8bcf5c6e6b99027110a20b1ef95d5f6607673ddc
> > Reviewed-on: https://chromium-review.googlesource.com/c/1411919
> > Reviewed-by: Morten Stenshorne <mstensho@chromium.org>
> > Commit-Queue: Morten Stenshorne <mstensho@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#623209}
> 
> TBR=fs@opera.com,mstensho@chromium.org
> 
> Change-Id: Ifd8aad2dc3c78703a7f544564417ceb15cddcdda
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Reviewed-on: https://chromium-review.googlesource.com/c/1414993
> Reviewed-by: Corentin Wallez <cwallez@chromium.org>
> Commit-Queue: Corentin Wallez <cwallez@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#623248}

TBR=fs@opera.com,cwallez@chromium.org,mstensho@chromium.org

Change-Id: Id247820a5c902209354452d495537ab02efb7605
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/1414939
Reviewed-by: Fredrik Söderquist <fs@opera.com>
Commit-Queue: Fredrik Söderquist <fs@opera.com>
Cr-Commit-Position: refs/heads/master@{#623251}
7 files changed