Ran GetIsolate/GetHeap removal script over all the header files included
into objects.cc. Affected classes include: ScriptContextTable
RuntimeCallTimerScope GlobalDictionaryShape Map LookupIterator
PrototypeIterator FixedArrayBuilder

Manually fixed up Map to mark its write operations as safe for
GetIsolate since they modify the object as so can't be done in RO_SPACE.

Bug: v8:7786
Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng;luci.v8.try:v8_linux_noi18n_rel_ng
Change-Id: I2fd0960f085d1bcb4cf54b3418899ac0217917ca
Reviewed-on: https://chromium-review.googlesource.com/1138076
Commit-Queue: Dan Elphick <delphick@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54488}

Add <root>_handle getters to ReadOnlyRoots, so an Isolate isn't required
to get a handle of a root.

Also convert one GetIsolate()->factory()->accessor() to
GetReadOnlyRoots().accessor_handle() in FixedArray.

Bug: v8:7786
Change-Id: I1b72c58f90eacf64be95abb65df91cf993178a93
Reviewed-on: https://chromium-review.googlesource.com/1129225
Commit-Queue: Dan Elphick <delphick@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54334}

This is a clean-up to completely remove the Heap accessors for roots
accessible via ReadOnlyRoots. Where previously ReadOnlyRoots called the
Heap accessor, now it accesses the roots array directly using the root
index (since ReadOnlyRoots is a friend of Heap).

Also clean up several cases where private Heap accessors were still
being used by Heap and its friends.

Bug: v8:7786
Change-Id: Iaca2e17b22822b30d395dec6250a4d5ae496c983
Reviewed-on: https://chromium-review.googlesource.com/1127172
Commit-Queue: Dan Elphick <delphick@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54297}

Moves STRUCT_LIST AND ALLOCATION_SITE_LIST into roots.h and adds access
to their associated maps using ReadOnlyRoots.

Also corrects the location of external_map, message_object_map,
empty_script, many_closures_cell, invalid_prototype_validity_cell and
builtins_constants_table which are not in RO_SPACE.

Finally this adds a convenience ReadOnlyRoots(Isolate*) constructor.

Bug: v8:7786
Change-Id: I4982dd0cbea2062a124605678599ba48831f020f
Reviewed-on: https://chromium-review.googlesource.com/1124319Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54178}

Adds a ReadOnlyRoots class trivially constructable from a Heap* or
Isolate* and which can be obtained from a any HeapObject which provides
access to roots objects that will always be in RO_SPACE. In the longer
term this object will be accessed via a global variable without
requiring an Isolate or using the memory address of a HeapObject to
infer it.

Moves the list macros in heap.h to roots.h and splits some of them into
two parts (read-only and mutable).

Convert cases of heap_object->GetHeap()->root_accessor() to
heap_objects->GetReadOnlyRoots().root_accessor().

Bug: v8:7786
Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
Change-Id: I14b01052adb2af9a5ec82b970e933d6a423d17a5
Reviewed-on: https://chromium-review.googlesource.com/1122127
Commit-Queue: Dan Elphick <delphick@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54160}