Update to Chromium version 88.0.4324.0 (#827102)

- Mac: Xcode 12.2 and the MacOS 11.0 SDK are now required for building.
- MacOS 10.10 (Yosemite) is no longer supported (see https://crbug.com/1126056).
- Flash is no longer supported (see https://www.chromium.org/flash-roadmap).

patch/patches/chrome_browser.patch

@@ -1,5 +1,5 @@
 diff --git chrome/browser/BUILD.gn chrome/browser/BUILD.gn
-index e462f7d8bef1..6c1c686f161c 100644
+index 16bd4c2717ee..65e309d23866 100644
 --- chrome/browser/BUILD.gn
 +++ chrome/browser/BUILD.gn
 @@ -12,6 +12,7 @@ import("//build/config/crypto.gni")
@@ -10,15 +10,15 @@ index e462f7d8bef1..6c1c686f161c 100644
  import("//chrome/browser/buildflags.gni")
  import("//chrome/browser/downgrade/buildflags.gni")
  import("//chrome/common/features.gni")
-@@ -1876,6 +1877,7 @@ static_library("browser") {
-     "//build:branding_buildflags",
+@@ -1912,6 +1913,7 @@ static_library("browser") {
      "//build:chromeos_buildflags",
+     "//build/config/compiler:compiler_buildflags",
      "//cc",
 +    "//cef/libcef/features",
      "//chrome:extra_resources",
      "//chrome:resources",
      "//chrome:strings",
-@@ -2354,6 +2356,10 @@ static_library("browser") {
+@@ -2424,6 +2426,10 @@ static_library("browser") {
      ]
    }
  
@@ -29,7 +29,7 @@ index e462f7d8bef1..6c1c686f161c 100644
    if (is_android) {
      sources += [
        "after_startup_task_utils_android.cc",
-@@ -4821,7 +4827,7 @@ static_library("browser") {
+@@ -4975,7 +4981,7 @@ static_library("browser") {
        ]
      }