Roll chromium_revision 12db4b522d..a8dab8a10f (1228976:1229078)

Change log: https://chromium.googlesource.com/chromium/src/+log/12db4b522d..a8dab8a10f
Full diff: https://chromium.googlesource.com/chromium/src/+/12db4b522d..a8dab8a10f

Changed dependencies
* src/buildtools: https://chromium.googlesource.com/chromium/src/buildtools/+log/ef503d1590..ed2855f2d6
* src/ios: https://chromium.googlesource.com/chromium/src/ios/+log/9e8cd3936a..2b7e234df1
* src/testing: https://chromium.googlesource.com/chromium/src/testing/+log/66f2a1e34a..35f6027ed8
* src/third_party: https://chromium.googlesource.com/chromium/src/third_party/+log/8f85a68136..885ea03968
* src/third_party/libc++/src: https://chromium.googlesource.com/external/github.com/llvm/llvm-project/libcxx.git/+log/0ec946fa26..9e4e987c28
DEPS diff: https://chromium.googlesource.com/chromium/src/+/12db4b522d..a8dab8a10f/DEPS

No update to Clang.

BUG=None

Change-Id: Ia46da377968533769d6d2dbf25e7bcf70d4f7b18
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/328640
Commit-Queue: Autoroller <chromium-webrtc-autoroll@webrtc-ci.iam.gserviceaccount.com>
Bot-Commit: Autoroller <chromium-webrtc-autoroll@webrtc-ci.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#41240}
diff --git a/DEPS b/DEPS
index fe37908..209ebe5 100644
--- a/DEPS
+++ b/DEPS
@@ -10,7 +10,7 @@
   # chromium waterfalls. More info at: crbug.com/570091.
   'checkout_configuration': 'default',
   'checkout_instrumented_libraries': 'checkout_linux and checkout_configuration == "default"',
-  'chromium_revision': '12db4b522d753755d388d831723c4ea5770caf82',
+  'chromium_revision': 'a8dab8a10ffe49a76ec5610cac5fcac6d8bf41c6',
 
   # Fetch the prebuilt binaries for llvm-cov and llvm-profdata. Needed to
   # process the raw profiles produced by instrumented targets (built with
@@ -54,20 +54,20 @@
   'src/build':
     'https://chromium.googlesource.com/chromium/src/build@8b922e8b997ee576660ca482418abfe332383a96',
   'src/buildtools':
-    'https://chromium.googlesource.com/chromium/src/buildtools@ef503d15906ec4248fa94033c01d8b7b39d815bf',
+    'https://chromium.googlesource.com/chromium/src/buildtools@ed2855f2d6b9792423000faf2350d2b92ff73abb',
   # Gradle 6.6.1. Used for testing Android Studio project generation for WebRTC.
   'src/examples/androidtests/third_party/gradle': {
     'url': 'https://chromium.googlesource.com/external/github.com/gradle/gradle.git@f2d1fb54a951d8b11d25748e4711bec8d128d7e3',
     'condition': 'checkout_android',
   },
   'src/ios': {
-    'url': 'https://chromium.googlesource.com/chromium/src/ios@9e8cd3936a48a27600163b6bea4416f4f81868a5',
+    'url': 'https://chromium.googlesource.com/chromium/src/ios@2b7e234df14b1ae361d2493f7acab9083e01d064',
     'condition': 'checkout_ios',
   },
   'src/testing':
-    'https://chromium.googlesource.com/chromium/src/testing@66f2a1e34a995fd5ff87eeeee64db8e61acfa9da',
+    'https://chromium.googlesource.com/chromium/src/testing@35f6027ed8fdbd821447d471a7117f466ffa6d73',
   'src/third_party':
-    'https://chromium.googlesource.com/chromium/src/third_party@8f85a6813660485dabed335fdd2f03ac2faa8ccb',
+    'https://chromium.googlesource.com/chromium/src/third_party@885ea03968b73ff2c6e99b67eb25aa20fa001cf2',
 
   'src/buildtools/linux64': {
     'packages': [
@@ -115,7 +115,7 @@
   'src/third_party/clang-format/script':
     'https://chromium.googlesource.com/external/github.com/llvm/llvm-project/clang/tools/clang-format.git@e5337933f2951cacd3aeacd238ce4578163ca0b9',
   'src/third_party/libc++/src':
-    'https://chromium.googlesource.com/external/github.com/llvm/llvm-project/libcxx.git@0ec946fa26f0ad25ad366e5f7acdec2ab8ceed2a',
+    'https://chromium.googlesource.com/external/github.com/llvm/llvm-project/libcxx.git@9e4e987c282a170f6daf8b3c8b52d101d2346f68',
   'src/third_party/libc++abi/src':
     'https://chromium.googlesource.com/external/github.com/llvm/llvm-project/libcxxabi.git@e6a7fd81edcf7c3effe2a815a1d7937cbeaacc59',
   'src/third_party/libunwind/src':