Add "Paste as plain text" into text selection toolbar overflow

content/browser/web_contents/web_contents_android.cc

 // Copyright 2013 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/web_contents/web_contents_android.h"
 
 #include <stdint.h>
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_array.h"
@@ skipping 254 matching lines @@
 }
 
 void WebContentsAndroid::Copy(JNIEnv* env, const JavaParamRef<jobject>& obj) {
   web_contents_->Copy();
 }
 
 void WebContentsAndroid::Paste(JNIEnv* env, const JavaParamRef<jobject>& obj) {
   web_contents_->Paste();
 }
 
+void WebContentsAndroid::PasteAsPlainText(JNIEnv* env,
+                                          const JavaParamRef<jobject>& obj) {
+  // Paste as plain text is actually paste text use the current text format

[boliu, 2017/05/03 00:44:44]

this does not actually explain why it's correct, should be something like "paste
as if user typed the characters, which should match current style of the caret
location"

+  // setting.
+  web_contents_->PasteAndMatchStyle();
+}
+
 void WebContentsAndroid::Replace(JNIEnv* env,
                                  const JavaParamRef<jobject>& obj,
                                  const JavaParamRef<jstring>& jstr) {
   web_contents_->Replace(base::android::ConvertJavaStringToUTF16(env, jstr));
 }
 
 void WebContentsAndroid::SelectAll(JNIEnv* env,
                                    const JavaParamRef<jobject>& obj) {
   web_contents_->SelectAll();
 }
@@ skipping 428 matching lines @@
       env, obj, callback, id, http_status_code, jurl, jbitmaps, jsizes);
 }
 
 void WebContentsAndroid::SetMediaSession(
     const ScopedJavaLocalRef<jobject>& j_media_session) {
   JNIEnv* env = base::android::AttachCurrentThread();
   Java_WebContentsImpl_setMediaSession(env, obj_, j_media_session);
 }
 
 }  // namespace content