[Android] Upstream the WebView find-in-page API implementation.

android_webview/lib/main/webview_entry_point.cc

 // Copyright (c) 2012 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 "android_webview/lib/main/aw_main_delegate.h"
 #include "android_webview/native/android_webview_jni_registrar.h"
 #include "base/android/jni_android.h"
+#include "base/command_line.h"
 #include "content/public/app/android_library_loader_hooks.h"
 #include "content/public/app/content_main.h"
+#include "content/public/common/content_switches.h"
 
 // This is called by the VM when the shared library is first loaded.
 // Most of the initialization is done in LibraryLoadedOnMainThread(), not here.
 JNI_EXPORT jint JNI_OnLoad(JavaVM* vm, void* reserved) {
   base::android::InitVM(vm);
   JNIEnv* env = base::android::AttachCurrentThread();
   if (!content::RegisterLibraryLoaderEntryHook(env))
     return -1;
 
   if (!android_webview::RegisterJni(env))
     return -1;
 
+  // Set the command line to enable synchronous API compatibility.
+  CommandLine::Init(0, NULL);
+  CommandLine::ForCurrentProcess()->AppendSwitch(
+      switches::kEnableWebViewSynchronousAPIs);
+
   content::SetContentMainDelegate(new android_webview::AwMainDelegate());
 
   return JNI_VERSION_1_4;
 }