Bump Chrome's deployment target to macOS 10.8.

build_overrides/build.gni

Index: build_overrides/build.gni
diff --git a/build_overrides/build.gni b/build_overrides/build.gni
index 68be7a2fdd21173e0561c0042b398ed947abad10..b797485877a363d431d830390b3414dcca561e41 100644
--- a/build_overrides/build.gni
+++ b/build_overrides/build.gni
@@ -2,13 +2,12 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+# Several dependencies of Chrome require a different min sdk and/or deployment
+# target when built as stand-alone projects. If this is ever not the case, these
+# variables can be removed.
 # See https://bugs.chromium.org/p/webrtc/issues/detail?id=5453.
-# Some WebRTC targets require the 10.7 deployment version of the Mac SDK
-# and a 10.11 min SDK, but those targets are only used in non-Chromium
-# builds. We can remove this when Chromium drops 10.6 support and also
-# requires 10.7.
 mac_sdk_min_build_override = "10.10"
-mac_deployment_target_build_override = "10.7"
+mac_deployment_target_build_override = "10.8"
 
 # Variable that can be used to support multiple build scenarios, like having
 # Chromium specific targets in a client project's GN file etc.
@@ -29,6 +28,5 @@ linux_use_bundled_binutils_override = true
 asan_suppressions_file = "//build/sanitizers/asan_suppressions.cc"
 lsan_suppressions_file = "//build/sanitizers/lsan_suppressions.cc"
 tsan_suppressions_file = "//build/sanitizers/tsan_suppressions.cc"
-
 # Uncomment these to specify a different lint suppressions file for android
 # lint_suppressions_file = path/to/your/suppressions/file/suppressions.xml