Implement window.print() on Android

printing/printing_context_android.h

Index: printing/printing_context_android.h
diff --git a/printing/printing_context_android.h b/printing/printing_context_android.h
index 32f11be7b766d1795c6df56aeb95aaa2c67b2386..d3e899d0cb2b3d922a906b32fe685845b6f6d7a6 100644
--- a/printing/printing_context_android.h
+++ b/printing/printing_context_android.h
@@ -14,8 +14,7 @@
 
 namespace printing {
 
-// Android subclass of PrintingContext.  The implementation for this header file
-// resides in Chrome for Android repository.  This class communicates with the
+// Android subclass of PrintingContext. This class communicates with the
 // Java side through JNI.
 class PRINTING_EXPORT PrintingContextAndroid : public PrintingContext {
  public:
@@ -30,7 +29,11 @@ class PRINTING_EXPORT PrintingContextAndroid : public PrintingContext {
   // printing operation is canceled.
   void AskUserForSettingsReply(JNIEnv* env, jobject obj, jboolean success);
 
+  // Called from Java, when a printing process initiated by a script finishes.
+  void ShowSystemDialogDone(JNIEnv* env, jobject obj);
+
   // PrintingContext implementation.
+  virtual void RequestSystemDialog(const PrintSettingsCallback& cb) override;
   virtual void AskUserForSettings(
       int max_pages,
       bool has_selection,