Roll pdfium/build/ dc8cb2c8b..acf607f7d (79 commits).

build_overrides/build.gni

Index: build_overrides/build.gni
diff --git a/build_overrides/build.gni b/build_overrides/build.gni
index a9e8000a859329c0c1bb088e214342cca91c599f..61d7814005773afe2251ff1f124cfe31229d4a72 100644
--- a/build_overrides/build.gni
+++ b/build_overrides/build.gni
@@ -40,4 +40,22 @@ declare_args() {
   # due to 4GiB file size limit, see https://crbug.com/648948.
   # Set this flag to true to skip the assertion.
   ignore_elf32_limitations = false
+
+  # Use the system install of Xcode for tools like ibtool, libtool, etc.
+  # This does not affect the compiler. When this variable is false, targets will
+  # instead use a hermetic install of Xcode. [The hermetic install can be
+  # obtained with gclient sync after setting the environment variable
+  # FORCE_MAC_TOOLCHAIN].
+  use_system_xcode = ""
+}
+
+if (use_system_xcode == "") {
+  if (target_os == "mac") {
+    _result =
+        exec_script("//build/mac/should_use_hermetic_xcode.py", [], "value")
+    use_system_xcode = _result == 0
+  }
+  if (target_os == "ios") {
+    use_system_xcode = true
+  }
 }