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

content/browser/web_contents/web_contents_android.cc

Index: content/browser/web_contents/web_contents_android.cc
diff --git a/content/browser/web_contents/web_contents_android.cc b/content/browser/web_contents/web_contents_android.cc
index 111773b0be67ace0112dd94124b5d1ebc9c99c69..4e6b56101b1159c2907ef5284d086d30eaf15390 100644
--- a/content/browser/web_contents/web_contents_android.cc
+++ b/content/browser/web_contents/web_contents_android.cc
@@ -272,6 +272,13 @@ 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) {