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

chrome/browser/chrome_content_browser_client.cc

Index: chrome/browser/chrome_content_browser_client.cc
diff --git a/chrome/browser/chrome_content_browser_client.cc b/chrome/browser/chrome_content_browser_client.cc
index 117a7d435a5e0a3d82caaf81721844e3e148ff5e..9b81a2c6b0296417d9dc26c20e4ca2902813966e 100644
--- a/chrome/browser/chrome_content_browser_client.cc
+++ b/chrome/browser/chrome_content_browser_client.cc
@@ -174,6 +174,7 @@
 #endif
 
 #if defined(OS_ANDROID)
+#include "base/android/apk_assets.h"
 #include "ui/base/ui_base_paths.h"
 #include "ui/gfx/android/device_display_info.h"
 #endif
@@ -2219,7 +2220,11 @@ void ChromeContentBrowserClient::GetAdditionalFileSystemBackends(
 void ChromeContentBrowserClient::GetAdditionalMappedFilesForChildProcess(
     const base::CommandLine& command_line,
     int child_process_id,
-    FileDescriptorInfo* mappings) {
+    FileDescriptorInfo* mappings
+#if defined(OS_ANDROID)
+    , std::map<int, base::MemoryMappedFile::Region>* regions
+#endif
+    ) {
 #if defined(V8_USE_EXTERNAL_STARTUP_DATA)
   if (v8_natives_fd_.get() == -1 || v8_snapshot_fd_.get() == -1) {
     int v8_natives_fd = -1;
@@ -2275,17 +2280,14 @@ void ChromeContentBrowserClient::GetAdditionalMappedFilesForChildProcess(
     }
   }
 
-  base::FilePath app_data_path;
-  PathService::Get(base::DIR_ANDROID_APP_DATA, &app_data_path);
-  DCHECK(!app_data_path.empty());
-
-  flags = base::File::FLAG_OPEN | base::File::FLAG_READ;
-  base::FilePath icudata_path =
-      app_data_path.AppendASCII(base::i18n::kIcuDataFileName);
-  base::File icudata_file(icudata_path, flags);
-  DCHECK(icudata_file.IsValid());
-  mappings->Transfer(kAndroidICUDataDescriptor,
-                     base::ScopedFD(icudata_file.TakePlatformFile()));
+  if (!icudtl_fd_.is_valid()) {
+    icudtl_fd_.reset(base::android::OpenApkAsset(base::i18n::kIcuDataFileName,
+                                                 &icudtl_region_));
+    DCHECK(icudtl_fd_.is_valid());
+  }
+  mappings->Share(kAndroidICUDataDescriptor, icudtl_fd_.get());
+  regions->insert(std::make_pair(kAndroidICUDataDescriptor, icudtl_region_));
+
 #else
   int crash_signal_fd = GetCrashSignalFD(command_line);
   if (crash_signal_fd >= 0) {