Revert of Moved logic for mapping child process FDs for ICU and V8 into child_process_launcher.cc

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 ca4790073fa03a83ac5fbc5f932ae5338f45324a..44f31f2f3902f9385c85917ebf861a86f724446f 100644
--- a/chrome/browser/chrome_content_browser_client.cc
+++ b/chrome/browser/chrome_content_browser_client.cc
@@ -12,6 +12,7 @@
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "base/files/scoped_file.h"
+#include "base/i18n/icu_util.h"
 #include "base/lazy_instance.h"
 #include "base/path_service.h"
 #include "base/prefs/pref_service.h"
@@ -124,6 +125,7 @@
 #include "content/public/common/url_utils.h"
 #include "content/public/common/web_preferences.h"
 #include "device/devices_app/devices_app.h"
+#include "gin/v8_initializer.h"
 #include "net/base/mime_util.h"
 #include "net/cookies/canonical_cookie.h"
 #include "net/cookies/cookie_options.h"
@@ -608,6 +610,10 @@
 
 ChromeContentBrowserClient::ChromeContentBrowserClient()
     :
+#if defined(OS_POSIX) && !defined(OS_MACOSX)
+      v8_natives_fd_(-1),
+      v8_snapshot_fd_(-1),
+#endif  // OS_POSIX && !OS_MACOSX
       weak_factory_(this) {
 #if defined(ENABLE_PLUGINS)
   for (size_t i = 0; i < arraysize(kPredefinedAllowedDevChannelOrigins); ++i)
@@ -1168,6 +1174,32 @@
 }
 
 }  // namespace
+
+// When Chrome is updated on non-Windows platforms, the new files (like
+// V8 natives and snapshot) can have the same names as the previous
+// versions. Since the renderers for an existing Chrome browser process
+// are likely not compatible with the new files, the browser keeps hold
+// of the old files using an open fd. This fd is passed to subprocesses
+// like renderers.  Here we add the flag to tell the subprocesses where
+// to find these file descriptors.
+void ChromeContentBrowserClient::AppendMappedFileCommandLineSwitches(
+    base::CommandLine* command_line) {
+#if defined(OS_POSIX) && !defined(OS_MACOSX)
+#if defined(V8_USE_EXTERNAL_STARTUP_DATA)
+  std::string process_type =
+      command_line->GetSwitchValueASCII(switches::kProcessType);
+  if (process_type != switches::kZygoteProcess) {
+    // We want to pass the natives by fd because after an update the file may
+    // be updated, but we want the newly launched renderers to get the old one,
+    // opened by the browser when it started.
+    DCHECK(natives_fd_exists());
+    command_line->AppendSwitch(::switches::kV8NativesPassedByFD);
+    if (snapshot_fd_exists())
+      command_line->AppendSwitch(::switches::kV8SnapshotPassedByFD);
+  }
+#endif  // V8_USE_EXTERNAL_STARTUP_DATA
+#endif  // OS_POSIX && !OS_MACOSX
+}
 
 void ChromeContentBrowserClient::AppendExtraCommandLineSwitches(
     base::CommandLine* command_line,
@@ -2214,6 +2246,24 @@
     const base::CommandLine& command_line,
     int child_process_id,
     FileDescriptorInfo* mappings) {
+#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);
+    }
+  }
+  // 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());
+  if (snapshot_fd_exists())
+    mappings->Share(kV8SnapshotDataDescriptor, v8_snapshot_fd_.get());
+#endif  // V8_USE_EXTERNAL_STARTUP_DATA
+
 #if defined(OS_ANDROID)
   base::FilePath data_path;
   PathService::Get(ui::DIR_RESOURCE_PAKS_ANDROID, &data_path);
@@ -2257,6 +2307,14 @@
   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()));
 #else
   int crash_signal_fd = GetCrashSignalFD(command_line);
   if (crash_signal_fd >= 0) {