Implement window.print() on Android

printing/printing_context_android.cc

Index: printing/printing_context_android.cc
diff --git a/printing/printing_context_android.cc b/printing/printing_context_android.cc
index 64139c8bfb837c708d0002bf4f85ff707a28e44e..89bab2922fb844b7d39a29ca3da9833709147831 100644
--- a/printing/printing_context_android.cc
+++ b/printing/printing_context_android.cc
@@ -79,6 +79,19 @@ PrintingContextAndroid::PrintingContextAndroid(Delegate* delegate)
 PrintingContextAndroid::~PrintingContextAndroid() {
 }
 
+void PrintingContextAndroid::RequestSystemDialog(
+    const PrintSettingsCallback& callback) {
+  callback_ = callback;
+
+  JNIEnv* env = base::android::AttachCurrentThread();
+  if (j_printing_context_.is_null()) {
+    j_printing_context_.Reset(Java_PrintingContext_create(
+        env,
+        reinterpret_cast<intptr_t>(this)));
+  }
+  Java_PrintingContext_showPrintDialog(env, j_printing_context_.obj());
+}
+
 void PrintingContextAndroid::AskUserForSettings(
     int max_pages,
     bool has_selection,
@@ -132,6 +145,12 @@ void PrintingContextAndroid::AskUserForSettingsReply(JNIEnv* env,
   callback_.Run(OK);
 }
 
+void PrintingContextAndroid::ShowSystemDialogDone(JNIEnv* env,
+                                                     jobject obj) {
+  LOG(INFO) << "DGN - PrintingContextAndroid::ShowSystemDialogDone";
+  callback_.Run(SYSTEM_DIALOG_DONE);

[dgn, 2014/11/28 11:51:15]

Returning OK works, but will make functions run in
PrintingMessageFilter::OnScriptedPrintReply that we don't need. Returning CANCEL
or FAILED would just be inappropriate when there is no explicit failure or
cancellation. Is that enough to justify the need for a new value? 

Alternatively, I could use completely different functions as callback that would
do only what I need (that is, send the reply message)

+}
+
 PrintingContext::Result PrintingContextAndroid::UseDefaultSettings() {
   DCHECK(!in_print_job_);