Allow base::Location in Blink.

We'd like to use base::Location and FROM_HERE in Blink instead of
blink::WebTraceLocation and BLINK_FROM_HERE.

Regarding a DEPS change in public/platform/scheduler, the only reference
of those names in public/ is in that directory, so I updated the DEPS
file there instead of the one in public/.

Bug: 794845
Change-Id: I4249abcb727186281229f41a0c81df649de8fbf7
Reviewed-on: https://chromium-review.googlesource.com/826924Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Taiju Tsuiki <tzik@chromium.org>
Reviewed-by: Alexander Timin <altimin@chromium.org>
Commit-Queue: Yuta Kitamura <yutak@chromium.org>
Cr-Commit-Position: refs/heads/master@{#524359}

third_party/WebKit/Source/DEPS

@@ -2,6 +2,7 @@ include_rules = [
     "+base/callback.h",
     "+base/callback_forward.h",
     "+base/debug",
+    "+base/location.h",
     "+base/macros.h",
     "+base/memory/weak_ptr.h",
     "+base/gtest_prod_util.h",

third_party/WebKit/Tools/Scripts/audit-non-blink-usage.py

@@ -31,6 +31,7 @@ _CONFIG = [
 
             # //base constructs that are allowed everywhere
             'base::AdoptRef',
+            'base::Location',
             'base::MakeRefCounted',
             'base::Optional',
             'base::SingleThreadTaskRunner',

third_party/WebKit/public/platform/scheduler/DEPS

 include_rules = [
     "+base/bind.h",
     "+base/callback.h",
+    "+base/location.h",
     "+base/macros.h",
     "+base/memory/ptr_util.h",
     "+base/memory/ref_counted.h",