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..bcf306b0ad9fa6be4172b077713fd1adda5224dd 100644
--- a/ui/base/resource/resource_bundle_android.cc
+++ b/ui/base/resource/resource_bundle_android.cc
@@ -2,28 +2,62 @@
 // 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/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/resource/resource_bundle.h"
 #include "ui/base/ui_base_paths.h"
 
 namespace ui {
 
+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;
+
+bool LoadFromApkOrFile(const char* apk_path,
+                       const base::FilePath* disk_path,
+                       int* fd_out,
+                       base::MemoryMappedFile::Region* region_out) {
+  DCHECK_EQ(*fd_out, -1) << "Attempt to load " << apk_path << " twice.";
+  if (apk_path != nullptr) {
+    *fd_out = base::android::OpenApkAsset(apk_path, region_out);
+  }
+  // For unit tests, the file exists on disk.
+  if (*fd_out < 0 && disk_path != nullptr) {
+    int flags = base::File::FLAG_OPEN | base::File::FLAG_READ;
+    *fd_out = base::File(*disk_path, flags).TakePlatformFile();
+    *region_out = base::MemoryMappedFile::Region::kWholeFile;
+  }
+  bool success = *fd_out >= 0;
+  if (!success) {
+    LOG(ERROR) << "Failed to open pak file: " << apk_path;
+  }
+  return success;
+}
+
+}  // namespace
+
 void ResourceBundle::LoadCommonResources() {
-  base::FilePath path;
-  PathService::Get(ui::DIR_RESOURCE_PAKS_ANDROID, &path);
-  AddDataPackFromPath(path.AppendASCII("chrome_100_percent.pak"),
-                      SCALE_FACTOR_100P);
+  base::FilePath disk_path;
+  PathService::Get(ui::DIR_RESOURCE_PAKS_ANDROID, &disk_path);
+  disk_path = disk_path.AppendASCII("chrome_100_percent.pak");
+  if (LoadFromApkOrFile("assets/chrome_100_percent.pak",
+                        &disk_path,
+                        &g_chrome_100_percent_fd,
+                        &g_chrome_100_percent_region)) {
+    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 +66,30 @@ gfx::Image& ResourceBundle::GetNativeImageNamed(int resource_id, ImageRTL rtl) {
   return GetImageNamed(resource_id);
 }
 
+void LoadMainAndroidPackFile(const char* path_within_apk,
+                             const base::FilePath& disk_file_path) {
+  if (LoadFromApkOrFile(path_within_apk,
+                        &disk_file_path,
+                        &g_resources_pack_fd,
+                        &g_resources_pack_region)) {
+    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(
@@ -44,4 +102,4 @@ bool RegisterResourceBundleAndroid(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
-}
+}  // namespace ui