Roll Perfetto from 0c0349252934 to a4cba6578f09 (6 revisions)

https://android.googlesource.com/platform/external/perfetto.git/+log/0c0349252934..a4cba6578f09

2020-08-07 treehugger-gerrit@google.com Merge "Importing flow events from protobuf to flow table"
2020-08-07 treehugger-gerrit@google.com Merge "Perfetto: parse GpuMemTotalEvent in trace processor"
2020-08-07 treehugger-gerrit@google.com Merge "Minor test cleanup, use protozero::HeapBuffered<Msg>"
2020-08-07 hjd@google.com Merge "ui: Remove thumbnail mode from heap profiles"
2020-08-07 hjd@google.com Merge "ui: Add instant event rendering"
2020-08-07 treehugger-gerrit@google.com Merge "Make client_ext ABI more stable."

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/+doc/master/autoroll/README.md

Cq-Include-Trybots: luci.chromium.try:linux-perfetto-rel
Bug: None
Tbr: perfetto-bugs@google.com
Change-Id: I8ff8e2e3bd8f4fa4ebd2539193944c57b3188276
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2343147Reviewed-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@{#796030}

DEPS

@@ -1248,7 +1248,7 @@ deps = {
   },
 
   'src/third_party/perfetto':
-    Var('android_git') + '/platform/external/perfetto.git' + '@' + '0c0349252934019978f01fe83ec8a2b83567fe63',
+    Var('android_git') + '/platform/external/perfetto.git' + '@' + 'a4cba6578f09d606d32fe32bb0a0c6283ea6d198',
 
   'src/third_party/perl': {
       'url': Var('chromium_git') + '/chromium/deps/perl.git' + '@' + '6f3e5028eb65d0b4c5fdd792106ac4c84eee1eb3',