Merged: Squashed multiple commits.

Merged: [build] Update MB fork with upstream changes
Revision: 41d9e8571419acd3547c9810c55c5516cc4dee79

Merged: [build] Drop Chromium-specific features from V8's MB fork
Revision: 1cd6fd9ff8e88bffa7cbec7131b85ff086dc128c

BUG=chromium:669910
LOG=N
NOTRY=true
NOPRESUBMIT=true
NOTREECHECKS=true
TBR=sergiyb@chromium.org

Change-Id: I6925724eeb44b7346c6f9f6bb5b9f964bd802e82
Reviewed-on: https://chromium-review.googlesource.com/781723
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/branch-heads/6.2@{#92}
Cr-Branched-From: efa2ac4-refs/heads/6.2.414@{#1}
Cr-Branched-From: a861ebb-refs/heads/master@{#47693}

tools/mb/docs/design_spec.md

@@ -411,9 +411,9 @@ config file change, however.
 ### Non-goals
 
 * MB is not intended to replace direct invocation of GN or GYP for
-  complicated build scenarios (aka ChromeOS), where multiple flags need
+  complicated build scenarios (a.k.a. Chrome OS), where multiple flags need
   to be set to user-defined paths for specific toolchains (e.g., where
-  ChromeOS needs to specify specific board types and compilers).
+  Chrome OS needs to specify specific board types and compilers).
 
 * MB is not intended at this time to be something developers use frequently,
   or to add a lot of features to. We hope to be able to get rid of it once

tools/mb/docs/user_guide.md

@@ -20,7 +20,7 @@ For more discussion of MB, see also [the design spec](design_spec.md).
 
 ### `mb analyze`
 
-`mb analyze` is responsible for determining what targets are affected by
+`mb analyze` is reponsible for determining what targets are affected by
 a list of files (e.g., the list of files in a patch on a trybot):
 
 ```
@@ -45,12 +45,12 @@ a single object with the following fields:
     reflect the stuff we might want to build *in addition to* the list
     passed in `test_targets`. Targets in this list will be treated 
     specially, in the following way: if a given target is a "meta"
-    (GN: group, GYP: none) target like 'blink_tests' or
-    'chromium_builder_tests', or even the ninja-specific 'all' target, 
-    then only the *dependencies* of the target that are affected by
-    the modified files will be rebuilt (not the target itself, which
-    might also cause unaffected dependencies to be rebuilt). An empty
-    list will be treated as if there are no additional targets to build.
+    (GN: group, GYP: none) target like 'blink_tests' or or even the
+    ninja-specific 'all' target, then only the *dependencies* of the
+    target that are affected by the modified files will be rebuilt
+    (not the target itself, which might also cause unaffected dependencies
+    to be rebuilt). An empty list will be treated as if there are no additional
+    targets to build.
     Empty lists for both `test_targets` and `additional_compile_targets`
     would cause no work to be done, so will result in an error.
   * `targets`: a legacy field that resembled a union of `compile_targets`
@@ -167,6 +167,21 @@ The `-f/--config-file` and `-q/--quiet` flags work as documented for
 This is mostly useful as a presubmit check and for verifying changes to
 the config file.
 
+### `mb gerrit-buildbucket-config`
+
+Generates a gerrit buildbucket configuration file and prints it to
+stdout. This file contains the list of trybots shown in gerrit's UI.
+
+The master copy of the buildbucket.config file lives
+in a separate branch of the chromium repository. Run `mb
+gerrit-buildbucket-config > buildbucket.config.new && git fetch origin
+refs/meta/config:refs/remotes/origin/meta/config && git checkout
+-t -b meta_config origin/meta/config && mv buildbucket.config.new
+buildbucket.config` to update the file.
+
+Note that after committing, `git cl upload` will not work. Instead, use `git
+push origin HEAD:refs/for/refs/meta/config` to upload the CL for review.
+
 ## Isolates and Swarming
 
 `mb gen` is also responsible for generating the `.isolate` and