Support null language for fallbackFontForChar's IPC wrapper

content/browser/renderer_host/sandbox_ipc_linux.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/renderer_host/sandbox_ipc_linux.h"
 
 #include <fcntl.h>
 #include <sys/poll.h>
 #include <sys/socket.h>
 #include <sys/stat.h>
@@ skipping 205 matching lines @@
     PickleIterator iter,
     const std::vector<base::ScopedFD*>& fds) {
   // The other side of this call is
   // content/common/child_process_sandbox_support_impl_linux.cc
 
   EnsureWebKitInitialized();
   WebUChar32 c;
   if (!pickle.ReadInt(&iter, &c))
     return;
 
-  std::string preferred_locale;
-  if (!pickle.ReadString(&iter, &preferred_locale))
+  bool hasLocale;
+  if (!pickle.ReadBool(&iter, &hasLocale))
     return;
 
   blink::WebFallbackFont fallbackFont;
-  WebFontInfo::fallbackFontForChar(c, preferred_locale.c_str(), &fallbackFont);
+  if (hasLocale) {
+    std::string preferred_locale;
+    if (!pickle.ReadString(&iter, &preferred_locale))
+      return;
+    WebFontInfo::fallbackFontForChar(
+        c, preferred_locale.c_str(), &fallbackFont);
+  } else {
+    WebFontInfo::fallbackFontForChar(c, 0, &fallbackFont);
+  }
 
   int pathIndex = FindOrAddPath(SkString(fallbackFont.filename.data()));
   fallbackFont.fontconfigInterfaceId = pathIndex;
 
   Pickle reply;
   if (fallbackFont.name.data()) {
     reply.WriteString(fallbackFont.name.data());
   } else {
     reply.WriteString(std::string());
   }
@@ skipping 168 matching lines @@
 }
 
 void SandboxIPCHandler::EnsureWebKitInitialized() {
   if (webkit_platform_support_)
     return;
   webkit_platform_support_.reset(new BlinkPlatformImpl);
   blink::initializeWithoutV8(webkit_platform_support_.get());
 }
 
 }  // namespace content