Roll src/third_party/perfetto df5f7f9e4e1a..c6be40a04209 (5 commits)

https://android.googlesource.com/platform/external/perfetto.git/+log/df5f7f9e4e1a..c6be40a04209

git log df5f7f9e4e1a..c6be40a04209 --date=short --first-parent --format='%ad %ae %s'
2020-02-20 treehugger-gerrit@google.com Merge "Stringify errors from libunwindstack."
2020-02-20 treehugger-gerrit@google.com Merge "Log errors enabling / disabling tracing."
2020-02-20 fmayer@google.com Merge "LOG on HardResetFtraceState."
2020-02-20 primiano@google.com Merge "UI: Add CSP policy"
2020-02-20 treehugger-gerrit@google.com Merge "core: Add DCHECKs for process ID to TraceWriter (+1 in TraceBuffer)"

Created with:
  gclient setdep -r src/third_party/perfetto@c6be40a04209

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/perfetto-chromium-autoroll
Please CC perfetto-bugs@google.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

Bug: None
Tbr: perfetto-bugs@google.com
Change-Id: Iaff45e3848cafe6ea1062c597e8242627558602e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2066088Reviewed-by: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Commit-Queue: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#743170}

DEPS

@@ -1237,7 +1237,7 @@ deps = {
   },
 
   'src/third_party/perfetto':
-    Var('android_git') + '/platform/external/perfetto.git' + '@' + 'df5f7f9e4e1a9559024f05ea89b6ed647ffd4cc6',
+    Var('android_git') + '/platform/external/perfetto.git' + '@' + 'c6be40a042098c9692111380d2d7fbc6267ce594',
 
   'src/third_party/perl': {
       'url': Var('chromium_git') + '/chromium/deps/perl.git' + '@' + '6f3e5028eb65d0b4c5fdd792106ac4c84eee1eb3',