Previous version was https://chromium-review.googlesource.com/502808

BUG=v8:5402

Change-Id: If327f4d7884577b7e5e6159372bf28a80cd21e51
Reviewed-on: https://chromium-review.googlesource.com/506073
Commit-Queue: Marja Hölttä <marja@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45369}

This reverts commit 7be0159e.

Reason for revert: Broke node by generating a broken debug-support.cc

Original change's description:
> [objects.h splitting] Move Map and related classes.
> 
> BUG=v8:5402
> 
> Change-Id: I64fae0a0271eb0f1b71f4ec5d9bd5d22deb1cf59
> Reviewed-on: https://chromium-review.googlesource.com/502808
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Reviewed-by: Igor Sheludko <ishell@chromium.org>
> Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
> Commit-Queue: Marja Hölttä <marja@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#45305}

TBR=marja@chromium.org,mstarzinger@chromium.org,jarin@chromium.org,ishell@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5402

Change-Id: Ifa65537447eb0a1ef947b9d0dae6f07a8b150968
Reviewed-on: https://chromium-review.googlesource.com/506011Reviewed-by: Marja Hölttä <marja@chromium.org>
Commit-Queue: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45307}

BUG=v8:5402

Change-Id: I64fae0a0271eb0f1b71f4ec5d9bd5d22deb1cf59
Reviewed-on: https://chromium-review.googlesource.com/502808Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45305}

These headers only need forward declarations.

BUG=v8:5294

Review-Url: https://codereview.chromium.org/2654253002
Cr-Commit-Position: refs/heads/master@{#42740}

Our Type class has a semantic and representational dimension.
Much code in src/ast, Crankshaft and Turbofan is based on it.
Going forward in Turbofan we'd like to remove representational information
entirely. To that end, new type AstType has been created to preserve
existing behavior for the benefit of Crankshaft and the AST.

BUG=

Review-Url: https://codereview.chromium.org/2302283002
Cr-Commit-Position: refs/heads/master@{#39135}

Minor improvements measured through by https://github.com/kpdecker/six-speed/blob/master/tests/object-assign/object-assign.es6. Mostly due to inlining of NowContains on the FieldType

Review URL: https://codereview.chromium.org/1703513002

Cr-Commit-Position: refs/heads/master@{#34060}

Review URL: https://codereview.chromium.org/1700923002

Cr-Commit-Position: refs/heads/master@{#34026}