Implement window.print() on Android

printing/printing_context_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 "printing/printing_context_android.h"
 
 #include <vector>
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_array.h"
@@ skipping 61 matching lines @@
 }
 
 PrintingContextAndroid::PrintingContextAndroid(Delegate* delegate)
     : PrintingContext(delegate) {
   // The constructor is run in the IO thread.
 }
 
 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,
     const PrintSettingsCallback& callback) {
   // This method is always run in the UI thread.
   callback_ = callback;
 
   JNIEnv* env = base::android::AttachCurrentThread();
   if (j_printing_context_.is_null()) {
     j_printing_context_.Reset(Java_PrintingContext_create(
@@ skipping 33 matching lines @@
   int dpi = Java_PrintingContext_getDpi(env, j_printing_context_.obj());
   int width = Java_PrintingContext_getWidth(env, j_printing_context_.obj());
   int height = Java_PrintingContext_getHeight(env, j_printing_context_.obj());
   width = Round(ConvertUnitDouble(width, kInchToMil, 1.0) * dpi);
   height = Round(ConvertUnitDouble(height, kInchToMil, 1.0) * dpi);
   SetSizes(&settings_, dpi, width, height);
 
   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_);
 
   ResetSettings();
   settings_.set_dpi(kDefaultPdfDpi);
   gfx::Size physical_size = GetPdfPaperSizeDeviceUnits();
   SetSizes(&settings_, kDefaultPdfDpi, physical_size.width(),
            physical_size.height());
   return OK;
 }
@@ skipping 94 matching lines @@
   // Intentional No-op.
   return NULL;
 }
 
 // static
 bool PrintingContextAndroid::RegisterPrintingContext(JNIEnv* env) {
    return RegisterNativesImpl(env);
 }
 
 }  // namespace printing