Reland "[base] Use FuzzedDataProvider included in LLVM package."

This reverts commit 0d648721.

Reason for revert: this didn't help, the iOS bots should either use the Chromium bundled Clang or don't build fuzzers

Original change's description:
> Revert "[base] Use FuzzedDataProvider included in LLVM package."
> 
> This reverts commit 20d2671d.
> 
> Reason for revert: Causes build failures on iOS bots, see: https://crbug.com/999096
> 
> Original change's description:
> > [base] Use FuzzedDataProvider included in LLVM package.
> > 
> > Bug: 991200
> > Change-Id: Iee88e3a81057d509e18a2875a3070c5abc17c959
> > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1774303
> > Auto-Submit: Max Moroz <mmoroz@chromium.org>
> > Commit-Queue: Lei Zhang <thestig@chromium.org>
> > Reviewed-by: Lei Zhang <thestig@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#691207}
> 
> TBR=thestig@chromium.org,mmoroz@chromium.org
> 
> Change-Id: I044f8863f8fa7e2bb9e70b0f33e73fdd8bfa2a29
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: 991200, 999096
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1776043
> Reviewed-by: Oskar Sundbom <ossu@chromium.org>
> Commit-Queue: Oskar Sundbom <ossu@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#691575}

TBR=thestig@chromium.org,mmoroz@chromium.org,ossu@chromium.org

Change-Id: Ic811649e40c0932146f8fc275e142f47adc3f5f8
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 991200, 999096
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1776203Reviewed-by: Max Moroz <mmoroz@chromium.org>
Commit-Queue: Max Moroz <mmoroz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#691615}

base/DEPS

@@ -17,10 +17,3 @@ include_rules = [
   # //base/util can use //base but not vice versa.
   "-util",
 ]
-
-specific_include_rules = {
-  # Dependencies specific for fuzz targets and other fuzzing-related code.
-  ".*fuzz.*": [
-    "+third_party/libFuzzer/src/utils",  # This contains FuzzedDataProvider.
-  ],
-}

base/pickle_fuzzer.cc

@@ -2,9 +2,10 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include <fuzzer/FuzzedDataProvider.h>
+
 #include "base/macros.h"
 #include "base/pickle.h"
-#include "third_party/libFuzzer/src/utils/FuzzedDataProvider.h"
 
 namespace {
 constexpr int kIterations = 16;

base/test/OWNERS

@@ -13,6 +13,3 @@ per-file BUILD.gn=file://base/test/android/OWNERS
 
 # Linux fontconfig changes
 per-file *fontconfig*=file://base/nix/OWNERS
-
-# FuzzedDataProvider helper class.
-per-file *fuzzed_data_provider*=file://testing/libfuzzer/OWNERS