Version 4.9.278

Performance and stability improvements on all platforms.

Cr-Commit-Position: refs/heads/4.9.278@{#1}
Cr-Branched-From: 66b0d03-refs/heads/master@{#33071}

Version 4.9.277

Fix 'illegal access' in Date constructor edge case (issue 4640).

Reland of Use ES2015-style TypedArray prototype chain (patchset #1 id:1 of https://codereview.chromium.org/1554523002/ ) (issue 4085).

Performance and stability improvements on all platforms.

Cr-Commit-Position: refs/heads/4.9.277@{#1}
Cr-Branched-From: 3d6f79b-refs/heads/master@{#33070}

Version 4.9.276

Reland "Clean up promises and fix an edge case bug (patchset v8#4 id:60001 of https://codereview.chromium.org/1488783002/ )" (issue 3641).

Performance and stability improvements on all platforms.

Cr-Commit-Position: refs/heads/4.9.276@{#1}
Cr-Branched-From: 797d109-refs/heads/master@{#33065}

Version 4.9.275

Performance and stability improvements on all platforms.

Cr-Commit-Position: refs/heads/4.9.275@{#1}
Cr-Branched-From: 974e50b-refs/heads/master@{#33064}

Version 4.9.274

Performance and stability improvements on all platforms.

Cr-Commit-Position: refs/heads/4.9.274@{#1}
Cr-Branched-From: a9f6993-refs/heads/master@{#33063}

Version 4.9.273

Performance and stability improvements on all platforms.

Cr-Commit-Position: refs/heads/4.9.273@{#1}
Cr-Branched-From: 6a51d31-refs/heads/master@{#33061}

Version 4.9.272

Performance and stability improvements on all platforms.

Cr-Commit-Position: refs/heads/4.9.272@{#1}
Cr-Branched-From: 5a49eb0-refs/heads/master@{#33060}

Version 4.9.271

Performance and stability improvements on all platforms.

Cr-Commit-Position: refs/heads/4.9.271@{#1}
Cr-Branched-From: b24fc48-refs/heads/master@{#33059}

Version 4.9.270

[crankshaft] Don't inline array resize operations if receiver's proto is not a JSObject (Chromium issue 571064).

Performance and stability improvements on all platforms.

Cr-Commit-Position: refs/heads/4.9.270@{#1}
Cr-Branched-From: bae0d6c-refs/heads/master@{#33058}

Version 4.9.269

[ic] Fixed receiver_map register trashing in KeyedStoreIC megamorphic (Chromium issue 571370).

Performance and stability improvements on all platforms.

Cr-Commit-Position: refs/heads/4.9.269@{#1}
Cr-Branched-From: c1aded3-refs/heads/master@{#33057}