Store and load icudtl.dat directly from the apk rather than extracting on start-up

build/config/android/rules.gni

Index: build/config/android/rules.gni
diff --git a/build/config/android/rules.gni b/build/config/android/rules.gni
index 99dbccef9ce117c6c245e17233db2de8a82f3578..b4cb75049fc7216eb80500d8b206aba1ffc146f8 100644
--- a/build/config/android/rules.gni
+++ b/build/config/android/rules.gni
@@ -1226,6 +1226,8 @@ template("android_java_prebuilt") {
 #     they are depended on through android_library or android_resources targets
 #     (and so not through builtin targets like 'action', 'group', etc).
 #   java_files: List of .java files to include in the apk.
+#   extensions_to_not_compress: List of extensions (e.g. "dat,bin") to leave
+#     uncompressed within the .apk (e.g. required to mmap).
 #   srcjar_deps: List of srcjar dependencies. The .java files in the srcjars
 #      will be added to java_files and be included in this apk.
 #   apk_name: Name for final apk.
@@ -1612,6 +1614,12 @@ template("android_apk") {
     dex_path = final_dex_path
     load_library_from_apk = _load_library_from_apk
     create_density_splits = _create_density_splits
+    if (defined(invoker.extensions_to_not_compress)) {
+      extensions_to_not_compress = invoker.extensions_to_not_compress
+    } else {
+      # Allow icu data to be loaded directly from the .apk.
+      extensions_to_not_compress = "dat"
+    }
 
     version_code = _version_code
     version_name = _version_name