Moved CoverageMode and TypeProfileMode enums to interface-types.h
to save one include in isolate.h. This reduces the expanded lines of code
count by ~45k.

Bug: v8:8834

R=yangguo@chromium.org

Change-Id: I399fe8cf66b1aec79bcb5831afd46a74e358244d
Reviewed-on: https://chromium-review.googlesource.com/c/1489072Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Maya Lekova <mslekova@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59886}

We didn't update the arguments count properly when changing the JSCall
node to a direct Call node.

Bug: chromium:936302, v8:8895
Change-Id: I59a39a07e41151d8eaa2e1a1ea7b1835e00fb501
Reviewed-on: https://chromium-review.googlesource.com/c/1491191Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59885}

This is a reland of 734a6575

Original change's description:
> Do not enqueue or run a microtask on detached contexts
>
> This CL disables EnqueueMicrotask and RunMicrotasks on detached
> contexts. That is, if an embedder call DetachGlobal() on a v8::Context,
> EnqueueMicrotask on that context will not take effect, and all Microtask
> that is enqueued before DetachGlobal will be cancelled.
>
> On Blink, this implies that a frame will no longer run a microtask after
> it's navigated away. OTOH, detached frames in Blink are not affected.
>
> Bug: v8:8124
> Change-Id: I5b00ceef5ea2afb87cf067a65eb95c29bf91176d
> Reviewed-on: https://chromium-review.googlesource.com/c/1416071
> Reviewed-by: Toon Verwaest <verwaest@chromium.org>
> Reviewed-by: Yang Guo <yangguo@chromium.org>
> Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
> Reviewed-by: Adam Klein <adamk@chromium.org>
> Commit-Queue: Taiju Tsuiki <tzik@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#59445}

Tbr: adamk@chromium.org, yangguo@chromium.org, verwaest@chromium.org
Bug: v8:8124
Change-Id: I959a18ae214f1385d5f453b3ed94772e60f71e0f
Reviewed-on: https://chromium-review.googlesource.com/c/1469544
Commit-Queue: Taiju Tsuiki <tzik@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59884}

Rolling v8/build: https://chromium.googlesource.com/chromium/src/build/+log/ebd384a..7cd7119

Rolling v8/test/wasm-js/data: https://chromium.googlesource.com/external/github.com/WebAssembly/spec/+log/4da0540..44dfa15

Rolling v8/third_party/catapult: https://chromium.googlesource.com/catapult/+log/a4323c9..f610057

Rolling v8/third_party/depot_tools: https://chromium.googlesource.com/chromium/tools/depot_tools/+log/95ea36e..be28670

TBR=machenbach@chromium.org,hablich@chromium.org,sergiyb@chromium.org

Change-Id: If1a818f05981ae7b58c117498fef2829ebbd909f
Reviewed-on: https://chromium-review.googlesource.com/c/1490598Reviewed-by: v8-ci-autoroll-builder <v8-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com>
Commit-Queue: v8-ci-autoroll-builder <v8-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#59883}

The master protocol description file is js_protocol.pdl, not .json

TBR=yangguo@chromium.org

Change-Id: Ibaef314a63c3e1665ed56bc8c66ca18a00c7fd4f
Reviewed-on: https://chromium-review.googlesource.com/c/1489976Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Commit-Queue: Alexei Filippov <alph@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59882}

This adds support for dynamically checking the newly introduced
is_safe_to_skip_adapt_arguments flag on the SharedFunctionInfo inside
the ArgumentsAdaptorTrampoline builtin, so that if there's an arguments
mismatch, but said bit is set, we can just massage the current stack
frame according to the SharedFunctionInfo and don't need to create an
arguments adaptor frame.

This improves the general (baseline) performance of calls with arguments
mismatches by up to 35%, as can be seen with the test case from the tracking
bug, which goes from around

  callUnderApplication: 608 ms.
  callOverApplication1: 633 ms.
  callOverApplication2: 635 ms.

to

  callUnderApplication: 390 ms.
  callOverApplication1: 439 ms.
  callOverApplication2: 443 ms.

when the TurboFan fast-path (that was previously introduced) is forcibly
disabled. That's a pretty solid baseline improvement and there's probably
still some room for further improvement (i.e. avoid loading the SFI multiple
times, etc.).

Drive-by-fix: Refactor and cleanup the ArgumentsAdaptorTrampoline
builtin a bit to make it more efficient and easier to read (it's still
pretty messy, but I don't wanna change too many things at once).

This is only the initial x64 port, since for ia32 we're really short on
registers and it might not even pay off (initial prototype shows a lot
less performance impact). The arm and arm64 port is in progress and will
land once ready.

Bug: v8:8834, v8:8895
Change-Id: I2e1c8e4767a808a43b932487fdedc0e44cdd35c5
Reviewed-on: https://chromium-review.googlesource.com/c/1488751
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59881}

OS::Allocate() previously was calling zx_vmo_replace_as_executable()
when executable access is requested. This breaks the case when the
OS::SetPermission() is called to mark that memory as executable later.
Updated it to call zx_vmo_replace_as_executable() for all VMOs.

This solution is not ideal, but it's consistent with other platforms,
so it's acceptable short-term.

Bug: v8:8899, chromium:934582
Change-Id: Ifeb818c93d8b9c80e73a057f5e6f3ca5a7b1c23f
Reviewed-on: https://chromium-review.googlesource.com/c/1483613Reviewed-by: Wez <wez@chromium.org>
Commit-Queue: Sergey Ulanov <sergeyu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59880}

TBR=petermarshall@chromium.org

Change-Id: I663735761c4ae730337b1381b52c99371eae2951
Notry: true
Bug: v8:5193
Reviewed-on: https://chromium-review.googlesource.com/c/1489084Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59879}

This one fails on Windows.

Bug: v8:5193
Change-Id: Ib028f8d7aa8a2d69a7324f9fcc6c5d03bc6f368c
Notry: true
Reviewed-on: https://chromium-review.googlesource.com/c/1489081
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59878}

R=mslekova@chromium.org

Bug: v8:8834
Change-Id: I51ff4441a80fd92bbdf400b5b92ff2d399250864
Reviewed-on: https://chromium-review.googlesource.com/c/1489077Reviewed-by: Maya Lekova <mslekova@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59877}

This one still fails too, whoops.

Bug: v8:5193
Change-Id: I07c0e55c8a1ca59311e0110c851b38bd9028c20f
Notry: true
Reviewed-on: https://chromium-review.googlesource.com/c/1489079
Commit-Queue: Peter Marshall <petermarshall@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59876}

Change-Id: I4bd02bdb68727b6242b0fe4b81fd522813b13f39
Bug: v8:8834
Reviewed-on: https://chromium-review.googlesource.com/c/1488755Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59875}

This one still fails, whoops.

Bug: v8:5193
Notry: true
Change-Id: Icd7ac2931e08efd176f0d37aea07c9bf30991d9b
Reviewed-on: https://chromium-review.googlesource.com/c/1489078Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59874}

I can't reproduce any of these flakes anymore on windows or linux.
Some are confirmed fixed with the same root cause as crbug.com/v8/8883.
Others are not reproducible anymore and were probably fixed by other
de-flaking and bugfixes in the last 6 months.

Bug: v8:5193, v8:7054
Change-Id: I23ce47a98f11f3637ccf4baf01ffab5c461a0ebd
Reviewed-on: https://chromium-review.googlesource.com/c/1489074Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59873}

NOTRY=true

Bug: v8:8889
Change-Id: I1faf4bcb8f573485915a8b79d551fbb4985a02a0
Reviewed-on: https://chromium-review.googlesource.com/c/1489075Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59872}

We somehow forgot to thread through the VectorSlotPair for the CALL_IC
based speculation feedback to CheckedTaggedToTaggedPointer. This was
showing for example with `String#concat()` where we ended up with an
endless deoptimization loop if the parameter was a Smi.

Bug: v8:8913
Change-Id: I84d90403f6fada9b435d4eb71c689edc3c34dc86
Reviewed-on: https://chromium-review.googlesource.com/c/1488770
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Mathias Bynens <mathias@chromium.org>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59871}

V8 used to use the microtask context when it runs EnqueueJob
step 2.
> Let job settings be some appropriate environment settings object.
https://html.spec.whatwg.org/multipage/webappapis.html#enqueuejob(queuename,-job,-arguments)

However, it's being updated to use the handler's context.
https://github.com/whatwg/html/issues/1426#issuecomment-340071080

Change-Id: I24840a28ef2c903539fe4ace74ae59da290f5109
Reviewed-on: https://chromium-review.googlesource.com/c/1465902Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Taiju Tsuiki <tzik@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59870}

R=mlippautz@chromium.org

Change-Id: Ic1d2fce007ddcb72f56ad257032e434c575a3f8d
Reviewed-on: https://chromium-review.googlesource.com/c/1456104
Commit-Queue: Yang Guo <yangguo@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59869}

The logic for removing while iterating is non-standard and
a left over from a previous index based loop. This patch
replaces it with a standard erase based version.

This fixes a runtime crash with MSVC that invalidates the
iterator and then asserts. This also makes the code safe
in case the last move can be redundant.

Change-Id: Ie6990e0d65a3b83a4b7da3e2e89ed4e60a6cd215
Reviewed-on: https://chromium-review.googlesource.com/c/1488762Reviewed-by: Ben Titzer <titzer@chromium.org>
Commit-Queue: Ben Titzer <titzer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59868}

Bug: v8:8834
Change-Id: I4d57b15f2d5058511a2c474897a52cac236a6a00
Reviewed-on: https://chromium-review.googlesource.com/c/1488767Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59867}

GetSymbol previously always internalized the underlying string, even if the
preparser does not need it. The most common case where this isn't needed is
property name parsing. This seems to speed up preparsing quite a bit.

For future reference: Property names in object literals still are needed due to
various checks (e.g., get 'constructor', duplicate __proto__, ...); as well as
cover grammar parsing (property names can turn into variable references). If we
turn all strings that the preparser needs to identify back into contextual
keywords we may be able to avoid the former.

Change-Id: I549e4600053de3136ca08d4915cc04db36d66a89
Reviewed-on: https://chromium-review.googlesource.com/c/1488764Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59866}

This CL introduces a new expression that can replace "std::string"
fields in other expressions. The main goal is to get SourcePositions
for identifiers to make them available in the language server.

The CL introduces a separate symbol "name", that allows to
incrementellay replace strings with name expression where needed. As
an example, variable delcarations now use a NameExpression for the
variable name.

R=danno@chromium.org, tebbi@chromium.org

Bug: v8:7793
Change-Id: I5b88bbaeac597b8e9760d2e01880e5e599ebf802
Reviewed-on: https://chromium-review.googlesource.com/c/1488752
Commit-Queue: Simon Zünd <szuend@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59865}

... which always contains constant value.

Bug: v8:8834
Change-Id: I27af24d07371b112d48eaab4d3a782a74af5fb20
Reviewed-on: https://chromium-review.googlesource.com/c/1487611Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59864}

When --concurrent_inlining is on, precompute (during serialization)
the list of receiver maps and the transition matrix of element
accesses.

Bug: v8:7790
Change-Id: I257eaea630f33831ab6600851ccdf297e17e35ca
Reviewed-on: https://chromium-review.googlesource.com/c/1475769
Commit-Queue: Georg Neis <neis@chromium.org>
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59863}

... as suggested by the bug's reporter.

Bug: chromium:935358
Change-Id: Iab9d207e4f55a395d0496ef5d5ea0e9b6783ae66
Reviewed-on: https://chromium-review.googlesource.com/c/1488757Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59862}

R=bmeurer@chromium.org

Bug: chromium:934201
Change-Id: I73048fef3afea5d06be88a2768d77f7e349daef5
Reviewed-on: https://chromium-review.googlesource.com/c/1488760Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59861}

By making EmptyIdentifierString (used for failure-mode parsing) point to the
empty_string() we can drop nullptr checks in the preparser. This is similar to
what the parser already does.

Change-Id: I4640f7ae6b24afc8d5275818caed0cca185ca72c
Reviewed-on: https://chromium-review.googlesource.com/c/1488759Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59860}

We'll remove the gcc version from the builder name in a follow up.

TBR=sergiyb@chromium.org
NOTRY=true

Bug: chromium:933093
Change-Id: I65359afd7245f155f7d1fd0519033ab8f8f736bb
Reviewed-on: https://chromium-review.googlesource.com/c/1488758Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Sergiy Belozorov <sergiyb@chromium.org>
Commit-Queue: Sergiy Belozorov <sergiyb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59859}

That way we can avoid allocating unreusable zone memory.

Change-Id: I0f30cbf5133026c63a9729bc45e728daa4740e9f
Reviewed-on: https://chromium-review.googlesource.com/c/1488756Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59858}

This reverts commit 32fc0acf.

Reason for revert:

https://ci.chromium.org/p/v8/builders/luci.v8.ci/V8-Blink%20Linux%2064/30270

layout test breakage:

https://test-results.appspot.com/data/layout_results/V8-Blink_Linux_64/30270/webkit_layout_tests%20%28with%20patch%29/layout-test-results/results.html

There is a dead node arriving in representation selection, which might indicate that the problem is not in this CL, but that this CL stirs up the node soup in such a way that dead code elimination gets confused.

Original change's description:
> Optimize `in` operator
> 
> This change implements optimizations for the `in` operator for packed array
> elements and object properties. It adds a new feedback slot kind and an IC
> path similar to KeyedLoadIC for handling the lookups. TurboFan uses the
> feedback to optimize based on the maps and keys.
> 
> For more details see:
> https://docs.google.com/document/d/1tIfzywY8AeNVcy_sen-5Xev21MeZwjcU8QhSdzHvXig
> 
> This can provide 10x performance improvements of on loops of the form:
> 
>     for (let i = 0; i < ary.length; ++i) {
>       if (i in ary) {
>         ...
>       }
>     }
> 
> 
> Bug: v8:8733
> Change-Id: I766bf865a547a059e5bce5399bb6112e5d9a85c8
> Reviewed-on: https://chromium-review.googlesource.com/c/1432598
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Reviewed-by: Igor Sheludko <ishell@chromium.org>
> Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
> Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
> Reviewed-by: Toon Verwaest <verwaest@chromium.org>
> Commit-Queue: Matt Gardner <magardn@microsoft.com>
> Cr-Commit-Position: refs/heads/master@{#59843}

TBR=ulan@chromium.org,rmcilroy@chromium.org,jkummerow@chromium.org,jarin@chromium.org,ishell@chromium.org,bmeurer@chromium.org,verwaest@chromium.org,magardn@microsoft.com

Change-Id: Ib2db974e5bed4c4a2b6b450f796bdc4b0b8fd562
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:8733
Reviewed-on: https://chromium-review.googlesource.com/c/1488761Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59857}

This flips the section codes for the exception section (part of the
exception handling proposal) and the data-count section (part of the
bulk memory proposal).

Also see the following discussions for the underlying motivation:
https://github.com/WebAssembly/bulk-memory-operations/pull/42
https://github.com/WebAssembly/exception-handling/issues/70

R=binji@chromium.org
BUG=v8:8868

Change-Id: I9f5f524e7aec067720346a5bb8d45c7c80a4c7a2
Reviewed-on: https://chromium-review.googlesource.com/c/1478207Reviewed-by: Ben Smith <binji@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59856}

This directory is created by ccls (language server for C++ and others).

R=sigurds@chromium.org

Change-Id: I2413921ca896ad2003fcfd10fdadb739f1af18c8
Reviewed-on: https://chromium-review.googlesource.com/c/1487151Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59855}

Remove EmbeddedVector from utils.h

Bug: v8:8834, v8:8912
Change-Id: I04e9f12121757bd0b87c68d7a4a5b213c2d8b686
Reviewed-on: https://chromium-review.googlesource.com/c/1486473Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59854}

Rolling v8/build: https://chromium.googlesource.com/chromium/src/build/+log/9f11dc3..ebd384a

TBR=machenbach@chromium.org,hablich@chromium.org,sergiyb@chromium.org

Change-Id: I1cb46f5fdd1604f0beb509e18a1bda31bbe8a2e1
Reviewed-on: https://chromium-review.googlesource.com/c/1485245Reviewed-by: Sergiy Belozorov <sergiyb@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: v8-ci-autoroll-builder <v8-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com>
Commit-Queue: Sergiy Belozorov <sergiyb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59853}

R=ahaas@chromium.org
TEST=mjsunit/regress/wasm/regress-935138
BUG=chromium:935138

Change-Id: I73465e0edcdfcd33b96764ffaf5f33519e424bb8
Reviewed-on: https://chromium-review.googlesource.com/c/1486471
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59852}

NOTRY=true
TBR=sergiyb@chromium.org

Bug: chromium:933093
Change-Id: I48236ef06c990526b72be418773d0a098c85178f
Reviewed-on: https://chromium-review.googlesource.com/c/1488754Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59851}

Change-Id: I2d5b54c88bece3e22c4ae25d7fba094647f64f52
Reviewed-on: https://chromium-review.googlesource.com/c/1487051Reviewed-by: Maya Lekova <mslekova@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59850}

MSVC 14.x and 15.x handle -0 correctly unless /fp:fast is used. /fp:precise
is the default.


bug: v8:3477, v8:8912
Change-Id: I242a1dfd845f750cab7c56f13107612259d44d23
Reviewed-on: https://chromium-review.googlesource.com/c/1487414Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59849}

This CL contains a basic Json parser used to read and write the
Json-RPC messages of the language server protocol.

This CL is part of the initial language server implementation but
submitted separately for easier review.

R=tebbi@chromium.org

Bug: v8:8880
Change-Id: Icea040975e1ed1d587954c3342d8d876e01c26b8
Reviewed-on: https://chromium-review.googlesource.com/c/1479956
Commit-Queue: Simon Zünd <szuend@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59848}

Turns --harmony-hashbang on by default.

Intent to ship: https://groups.google.com/d/msg/v8-dev/hlCVa_XZ3TM/UWjjyOq3FwAJ
ChromeStatus page: https://www.chromestatus.com/feature/5134505706782720

BUG=v8:8523
R=gsathya@chromium.org, mathias@chromium.org, adamk@chromium.org

Change-Id: I821f69e45eb0a63a3f49181e2b88b0bcd091af2c
Reviewed-on: https://chromium-review.googlesource.com/c/1486113Reviewed-by: Adam Klein <adamk@chromium.org>
Reviewed-by: Mathias Bynens <mathias@chromium.org>
Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
Commit-Queue: Caitlin Potter <caitp@igalia.com>
Cr-Commit-Position: refs/heads/master@{#59847}