Allow startup with missing V8 snapshot file.

extensions/shell/browser/shell_content_browser_client.cc

Index: extensions/shell/browser/shell_content_browser_client.cc
diff --git a/extensions/shell/browser/shell_content_browser_client.cc b/extensions/shell/browser/shell_content_browser_client.cc
index dbb7f6f733eddd2172d421fe01c1eeeddacc6e44..b978bfc27c5d59a2d4d27f574d95bdce2b6d9cbb 100644
--- a/extensions/shell/browser/shell_content_browser_client.cc
+++ b/extensions/shell/browser/shell_content_browser_client.cc
@@ -212,8 +212,12 @@ void ShellContentBrowserClient::AppendExtraCommandLineSwitches(
 #if defined(OS_POSIX) && !defined(OS_MACOSX)
 #if defined(V8_USE_EXTERNAL_STARTUP_DATA)
   if (process_type != ::switches::kZygoteProcess) {
-    command_line->AppendSwitch(::switches::kV8NativesPassedByFD);
-    command_line->AppendSwitch(::switches::kV8SnapshotPassedByFD);
+    if (v8_natives_fd_.get() != -1) {
+      command_line->AppendSwitch(::switches::kV8NativesPassedByFD);
+    }
+    if (v8_snapshot_fd_.get() != -1) {
+      command_line->AppendSwitch(::switches::kV8SnapshotPassedByFD);
+    }
   }
 #endif  // V8_USE_EXTERNAL_STARTUP_DATA
 #endif  // OS_POSIX && !OS_MACOSX
@@ -258,7 +262,7 @@ void ShellContentBrowserClient::GetAdditionalMappedFilesForChildProcess(
     int child_process_id,
     content::FileDescriptorInfo* mappings) {
 #if defined(V8_USE_EXTERNAL_STARTUP_DATA)
-  if (v8_natives_fd_.get() == -1 || v8_snapshot_fd_.get() == -1) {
+  if (v8_natives_fd_.get() == -1) {
     int v8_natives_fd = -1;
     int v8_snapshot_fd = -1;
     if (gin::V8Initializer::OpenV8FilesForChildProcesses(&v8_natives_fd,
@@ -267,7 +271,7 @@ void ShellContentBrowserClient::GetAdditionalMappedFilesForChildProcess(
       v8_snapshot_fd_.reset(v8_snapshot_fd);
     }
   }
-  DCHECK(v8_natives_fd_.get() != -1 && v8_snapshot_fd_.get() != -1);
+  DCHECK(v8_natives_fd_.get() != -1);
   mappings->Share(kV8NativesDataDescriptor, v8_natives_fd_.get());
   mappings->Share(kV8SnapshotDataDescriptor, v8_snapshot_fd_.get());
 #endif  // V8_USE_EXTERNAL_STARTUP_DATA