Load v8 snapshots directly from APK (and store them uncompressed)

ash/shell/content_client/shell_content_browser_client.cc

Index: ash/shell/content_client/shell_content_browser_client.cc
diff --git a/ash/shell/content_client/shell_content_browser_client.cc b/ash/shell/content_client/shell_content_browser_client.cc
index 633094783f4d573cba3c0daf66bc2c3110f13bbd..8ab62c1a8ba5707c90a8b4fbc5e6a943e0ecb16f 100644
--- a/ash/shell/content_client/shell_content_browser_client.cc
+++ b/ash/shell/content_client/shell_content_browser_client.cc
@@ -16,12 +16,7 @@ namespace ash {
 namespace shell {
 
 ShellContentBrowserClient::ShellContentBrowserClient()
-    :
-#if defined(OS_POSIX) && !defined(OS_MACOSX)
-      v8_natives_fd_(-1),
-      v8_snapshot_fd_(-1),
-#endif  // OS_POSIX && !OS_MACOSX
-      shell_browser_main_parts_(nullptr) {
+    : shell_browser_main_parts_(nullptr) {
 }
 
 ShellContentBrowserClient::~ShellContentBrowserClient() {
@@ -50,10 +45,11 @@ void ShellContentBrowserClient::AppendMappedFileCommandLineSwitches(
   std::string process_type =
       command_line->GetSwitchValueASCII(switches::kProcessType);
   if (process_type != switches::kZygoteProcess) {
-    DCHECK(natives_fd_exists());
+    DCHECK(v8_files_.natives_fd.is_valid());
     command_line->AppendSwitch(::switches::kV8NativesPassedByFD);
-    if (snapshot_fd_exists())
+    if (v8_files_.snapshot_fd.is_valid()) {
       command_line->AppendSwitch(::switches::kV8SnapshotPassedByFD);
+    }
   }
 #endif  // V8_USE_EXTERNAL_STARTUP_DATA
 #endif  // OS_POSIX && !OS_MACOSX
@@ -69,20 +65,22 @@ void ShellContentBrowserClient::GetAdditionalMappedFilesForChildProcess(
 #endif
     ) {
 #if defined(V8_USE_EXTERNAL_STARTUP_DATA)
-  if (!natives_fd_exists()) {
-    int v8_natives_fd = -1;
-    int v8_snapshot_fd = -1;
-    if (gin::V8Initializer::OpenV8FilesForChildProcesses(&v8_natives_fd,
-                                                         &v8_snapshot_fd)) {
-      v8_natives_fd_.reset(v8_natives_fd);
-      v8_snapshot_fd_.reset(v8_snapshot_fd);
-    }
+  if (!v8_files_.natives_fd.is_valid()) {
+    gin::V8Initializer::OpenV8FilesForChildProcesses(&v8_files_);
+  }
+  DCHECK(v8_files_.natives_fd.is_valid());
+  mappings->Share(kV8NativesDataDescriptor, v8_files_.natives_fd.get());
+#if defined(OS_ANDROID)
+  regions->insert(
+      std::make_pair(kV8NativesDataDescriptor, v8_files_.natives_region));
+#endif
+  if (v8_files_.snapshot_fd.is_valid()) {
+    mappings->Share(kV8SnapshotDataDescriptor, v8_files_.snapshot_fd.get());
+#if defined(OS_ANDROID)
+    regions->insert(
+        std::make_pair(kV8SnapshotDataDescriptor, v8_files_.snapshot_region));
+#endif
   }
-  // V8 can't start up without the source of the natives, but it can
-  // start up (slower) without the snapshot.
-  DCHECK(natives_fd_exists());
-  mappings->Share(kV8NativesDataDescriptor, v8_natives_fd_.get());
-  mappings->Share(kV8SnapshotDataDescriptor, v8_snapshot_fd_.get());
 #endif  // V8_USE_EXTERNAL_STARTUP_DATA
 }
 #endif  // OS_POSIX && !OS_MACOSX