harmony-scoping: Implement debugger support for script scope.

We add a new ScopeType, ScopeType.Script. The scope with
ScopeType.Script is always present in the scope chain (ScopeIterator
fakes it if neededi - i.e. if ScriptContext for a script has not been
allocated since that script has no lexical declarations).
ScriptScope reflects ScriptContextTable.

R=yurys@chromium.org,yangguo@chromium.org
BUG=v8:3690
LOG=N

Review URL: https://codereview.chromium.org/726643002

Cr-Commit-Position: refs/heads/master@{#25383}
Add a cctest for using a C++ FunctionCallback as an Object.observe observer

R=rossberg@chromium.org
BUG=v8:3076
LOG=n

Review URL: https://codereview.chromium.org/733483003

Cr-Commit-Position: refs/heads/master@{#25384}
[x64] Recognize MOVSXWL.

Also add some debug code to verify correct zero extension of 32-bit
moves.

TEST=mjsunit/asm
R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/736623002

Cr-Commit-Position: refs/heads/master@{#25385}
[x64] Recognize MOVSXBL.

TEST=mjsunit/asm
R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/728103007

Cr-Commit-Position: refs/heads/master@{#25386}
Hydrogen should recognize literal smi arrays as fast literals.

R=hpayer@chromium.org

Review URL: https://codereview.chromium.org/726423002

Cr-Commit-Position: refs/heads/master@{#25387}
[turbofan] Avoid useless sign extension after sign extended load.

TEST=unittests
R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/735623002

Cr-Commit-Position: refs/heads/master@{#25388}
Allow stepping into Promise handlers.

BUG=chromium:432468
R=yangguo@chromium.org, adamk@chromium.org, arv@chromium.org
LOG=N

Review URL: https://codereview.chromium.org/734163002

Cr-Commit-Position: refs/heads/master@{#25389}
[turbofan] Push JSToNumber conversions into Phis.

This essentially performs the following transformation

  JSToNumber(phi(x1,...,xn,control):primitive)
    => phi(JSToNumber(x1),...,JSToNumber(xn),control):number

which is similar to what we already do for JSToBoolean.

TEST=mjsunit/asm
R=svenpanne@chromium.org
BUG=

Review URL: https://codereview.chromium.org/732463003

Cr-Commit-Position: refs/heads/master@{#25390}
Use FlatStringReader in JSON stringifier.

R=ishell@chromium.org

Review URL: https://codereview.chromium.org/736543003

Cr-Commit-Position: refs/heads/master@{#25391}
Use a stub in crankshaft for grow store arrays.

We were deopting without learning anything.

BUG=v8:3417
LOG=N
R=danno@chromium.org

Review URL: https://codereview.chromium.org/368263003

Cr-Commit-Position: refs/heads/master@{#25392}
Revert "Use a stub in crankshaft for grow store arrays."

This reverts commit d40204f84c0f6fad171ba8ace587f902bd5b14bc.

TBR=danno@chromium.org

Review URL: https://codereview.chromium.org/735653003

Cr-Commit-Position: refs/heads/master@{#25393}
Fix IC handler cache clearing for JSBuiltinsObject

The clearing mechanism relies on comparing the cached handler with the installed handler. If we try to preserve monomorphism by pretending that the IC was in uninitialized state, then it will go premonomorphic first, which means on the next miss there's no installed handler available to compare against. Instead, pretend it was premonomorphic, so the comparison will happen right away, will fail as it should, and the cached handler will be cleared.

Thanks to Weiliang for starting the investigation that led to this.

R=verwaest@chromium.org

Review URL: https://codereview.chromium.org/730383002

Cr-Commit-Position: refs/heads/master@{#25394}
Fix include mistakes

1) Missing <stdio.h> while using fopen, fclose, fseek etc
2) platform-linux.cc includes <sys/types.h> wtice

BUG=v8:3691

Review URL: https://codereview.chromium.org/716123003

Cr-Commit-Position: refs/heads/master@{#25395}
Use 16 instead of 4 for determining member offsets.

This avoids UBSan warnings about unaligned memory access.

BUG=

Review URL: https://codereview.chromium.org/734873002

Cr-Commit-Position: refs/heads/master@{#25396}
Re-land r25392 Use a stub in crankshaft for grow store arrays.

Code was vulnerable to different evaluation order in Clang.

R=danno@chromium.org

Review URL: https://codereview.chromium.org/726693004

Cr-Commit-Position: refs/heads/master@{#25397}
Prototype for a client-side performance trybot script.

BUG=chromium:374740
LOG=n
TEST=tools/try_perf.py sunspider octane
R=phajdan.jr@chromium.org

Review URL: https://codereview.chromium.org/734403002

Cr-Commit-Position: refs/heads/master@{#25398}
Fix loop information computation for floating loops.

R=jarin@chromium.org
TEST=cctest/test-scheduler/LoopedFloatingDiamond3

Review URL: https://codereview.chromium.org/726953002

Cr-Commit-Position: refs/heads/master@{#25399}
Fix disabling all break points from within the debug event callback.

BUG=chromium:432493
LOG=Y

Review URL: https://codereview.chromium.org/728103008

Cr-Commit-Position: refs/heads/master@{#25400}
Remove ambiguous getter for operator value counts.

R=titzer@chromium.org

Review URL: https://codereview.chromium.org/735583003

Cr-Commit-Position: refs/heads/master@{#25401}
v8::String::Concat must not throw.

R=dcarney@chromium.org
BUG=chromium:420240
LOG=Y
API=v8::String::Concat may return empty handle on overflow.

Review URL: https://codereview.chromium.org/735763002

Cr-Commit-Position: refs/heads/master@{#25402}