Update DEPS entry for tracing to point at correct location

While not really fitting our directory layout, the DEPS entry needs to
be at exactly the same position as it is in chromium, otherwise either
standalone or chromium build won't work :-/

BUG=none
R=machenbach@chromium.org
LOG=y

Review URL: https://codereview.chromium.org/1526843004

Cr-Commit-Position: refs/heads/master@{#32896}

.gitignore

@@ -40,6 +40,7 @@ gcsuspects
 shell
 shell_g
 /_*
+/base/trace_event/common
 /build/Debug
 /build/gyp
 /build/ipch/
@@ -51,7 +52,6 @@ shell_g
 /out
 /perf.data
 /perf.data.old
-/src/tracing/common
 /test/benchmarks/data
 /test/mozilla/data
 /test/promises-aplus/promises-tests

DEPS

@@ -14,7 +14,7 @@ deps = {
   "v8/buildtools":
     Var("git_url") + "/chromium/buildtools.git" + "@" + "68e3c238a5ab347436762cb929316aa55ca72563",
   # TODO(fmeawad): this dependency is not currently used. Added to allow for developement of the V8 Tracing system.
-  "v8/src/tracing/common":
+  "v8/base/trace_event/common":
     Var("git_url") + "/chromium/src/base/trace_event/common.git" + "@" + "d83d44b13d07c2fd0a40101a7deef9b93b841732",
   "v8/tools/swarming_client":
     Var('git_url') + '/external/swarming.client.git' + '@' + "9cdd76171e517a430a72dcd7d66ade67e109aa00",