Load non-locale .pak files directly from the .apk on Android (rather than extracting on start-up).

ui/base/resource/resource_bundle_android.cc

Index: ui/base/resource/resource_bundle_android.cc
diff --git a/ui/base/resource/resource_bundle_android.cc b/ui/base/resource/resource_bundle_android.cc
index 9dc036eeded50c7ce4431733c5d5949e9d766463..50dfc2223636107d80e1d74b923524e6d4be8e4e 100644
--- a/ui/base/resource/resource_bundle_android.cc
+++ b/ui/base/resource/resource_bundle_android.cc
@@ -2,28 +2,34 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "ui/base/resource/resource_bundle.h"
-
-#include <string>
+#include "ui/base/resource/resource_bundle_android.h"
 
+#include "base/android/apk_assets.h"
 #include "base/android/jni_android.h"
 #include "base/android/jni_string.h"
-#include "base/files/file_path.h"
-#include "base/files/file_util.h"
+//#include "base/files/file_util.h"

[Yaron, 2015/06/17 14:12:28]

remove

[agrieve, 2015/06/17 14:35:40]

Done.

 #include "base/logging.h"
-#include "base/path_service.h"
-#include "base/strings/stringprintf.h"
 #include "jni/ResourceBundle_jni.h"
-#include "ui/base/resource/resource_handle.h"
-#include "ui/base/ui_base_paths.h"
+#include "ui/base/resource/resource_bundle.h"
+
+namespace {
+// It is okay to cache and share these file descriptors since the
+// ResourceBundle singleton never closes the handles.
+int g_chrome_100_percent_fd = -1;
+int g_resources_pack_fd = -1;
+base::MemoryMappedFile::Region g_chrome_100_percent_region;
+base::MemoryMappedFile::Region g_resources_pack_region;
+}
 
 namespace ui {
 
 void ResourceBundle::LoadCommonResources() {
-  base::FilePath path;
-  PathService::Get(ui::DIR_RESOURCE_PAKS_ANDROID, &path);

[Yaron, 2015/06/17 14:12:28]

Will this constant only be removed when language paks are loaded from apk? Or
actually, language paks would only be loaded from apk for ChromeModern, right?

[agrieve, 2015/06/17 14:35:40]

Only for ChromeModern, and we can't remove it unless we change all the tests to
load from apk rather than use isolate logic (which would be a lot of build logic
work - maybe wait for GN if we're going to do this...)

-  AddDataPackFromPath(path.AppendASCII("chrome_100_percent.pak"),
-                      SCALE_FACTOR_100P);
+  DCHECK_EQ(g_chrome_100_percent_fd, -1);
+  g_chrome_100_percent_fd = base::android::OpenApkAsset(
+      "assets/chrome_100_percent.pak", &g_chrome_100_percent_region);

[Yaron, 2015/06/17 14:12:28]

That's odd. I'm surprised that ui/ is dealing with "chrome" code and not having
it injected but it looks like that was already the case.

[agrieve, 2015/06/17 14:35:40]

That caught me too. I think the original intention was that there was no
dependency, but then LoadCommonResources is defined by each _platform.cc file.
Maybe that was added later on?

Considered following the same pattern for LoadMainPackFile(), but didn't want to
further the layering violation if infact it is one.

+  DCHECK_GE(g_chrome_100_percent_fd, 0);
+  AddDataPackFromFileRegion(base::File(g_chrome_100_percent_fd),
+                            g_chrome_100_percent_region, SCALE_FACTOR_100P);
 }
 
 gfx::Image& ResourceBundle::GetNativeImageNamed(int resource_id, ImageRTL rtl) {
@@ -32,6 +38,28 @@ gfx::Image& ResourceBundle::GetNativeImageNamed(int resource_id, ImageRTL rtl) {
   return GetImageNamed(resource_id);
 }
 
+void LoadMainAndroidPackFile() {
+  DCHECK_EQ(g_resources_pack_fd, -1);
+  g_resources_pack_fd = base::android::OpenApkAsset("assets/resources.pak",
+                                                    &g_resources_pack_region);
+  DCHECK_GE(g_resources_pack_fd, 0);
+  ResourceBundle::GetSharedInstance().AddDataPackFromFileRegion(
+      base::File(g_resources_pack_fd), g_resources_pack_region,
+      SCALE_FACTOR_NONE);
+}
+
+int GetMainAndroidPackFd(base::MemoryMappedFile::Region* out_region) {
+  DCHECK_GE(g_resources_pack_fd, 0);
+  *out_region = g_resources_pack_region;
+  return g_resources_pack_fd;
+}
+
+int GetCommonResourcesPackFd(base::MemoryMappedFile::Region* out_region) {
+  DCHECK_GE(g_chrome_100_percent_fd, 0);
+  *out_region = g_chrome_100_percent_region;
+  return g_chrome_100_percent_fd;
+}
+
 bool AssetContainedInApk(const std::string& filename) {
   JNIEnv* env = base::android::AttachCurrentThread();
   return Java_ResourceBundle_assetContainedInApk(