Implement window.print() on Android

chrome/renderer/printing/print_web_view_helper.cc

Index: chrome/renderer/printing/print_web_view_helper.cc
diff --git a/chrome/renderer/printing/print_web_view_helper.cc b/chrome/renderer/printing/print_web_view_helper.cc
index 201e4c25cfc9c3bcd65485912053db37fa698538..8e0ba5a66c45ff113d881e1d06fedb49a6795819 100644
--- a/chrome/renderer/printing/print_web_view_helper.cc
+++ b/chrome/renderer/printing/print_web_view_helper.cc
@@ -67,6 +67,13 @@ enum PrintPreviewHelperEvents {
 
 const double kMinDpi = 1.0;
 
+#if defined(OS_ANDROID)
+// Used to trigger the android system dialog from window.print()
+const bool g_is_system_specific_flow_enabled = true;

[Vitaly Buka (NO REVIEWS), 2014/12/09 23:46:48]

If I read the code correctly you just send value of "defined(OS_ANDROID)" to
printing_context. But OS_ANDROID is defined there.

So seems this entire file could be reverted.

[dgn, 2014/12/10 18:12:52]

The parameter I added to the |Print()| function has false as a default value so
that I would not affect existing calls. So what I wanted is to have the value
set to |true| only when a call is coming from window.print() on Android. The
|Print()| function is called when using the "Print..." menu item, so I can't
just #ifdef it in that function.

I can put the #ifdef in PrintPage() though. That's the last window.print()
specific call before the common code path. I wanted to be coherent with
|g_is_preview_enabled|, but mine is constant and used only in one place so
that's not useful.

+#else
+const bool g_is_system_specific_flow_enabled = false;
+#endif
+
 #if !defined(ENABLE_PRINT_PREVIEW)
 bool g_is_preview_enabled_ = false;
 #else
@@ -818,9 +825,6 @@ void PrintWebViewHelper::DisablePreview() {
 
 bool PrintWebViewHelper::IsScriptInitiatedPrintAllowed(
     blink::WebFrame* frame, bool user_initiated) {
-#if defined(OS_ANDROID)
-  return false;
-#endif  // defined(OS_ANDROID)
   // If preview is enabled, then the print dialog is tab modal, and the user
   // can always close the tab on a mis-behaving page (the system print dialog
   // is app modal). If the print was initiated through user action, don't
@@ -858,7 +862,7 @@ void PrintWebViewHelper::PrintPage(blink::WebLocalFrame* frame,
     return;
 
   if (!g_is_preview_enabled_) {
-    Print(frame, blink::WebNode());
+    Print(frame, blink::WebNode(), g_is_system_specific_flow_enabled);
   } else {
     print_preview_context_.InitWithFrame(frame);
     RequestPrintPreview(PRINT_PREVIEW_SCRIPTED);
@@ -968,6 +972,7 @@ bool PrintWebViewHelper::GetPrintFrame(blink::WebLocalFrame** frame) {
 
 #if defined(ENABLE_BASIC_PRINTING)
 void PrintWebViewHelper::OnPrintPages() {
+  DLOG(INFO) << "DGN - OnPrintPages - Call from PrintManager";
   blink::WebLocalFrame* frame;
   if (!GetPrintFrame(&frame))
     return;
@@ -1275,10 +1280,15 @@ void PrintWebViewHelper::PrintNode(const blink::WebNode& node) {
 }
 
 void PrintWebViewHelper::Print(blink::WebLocalFrame* frame,
-                               const blink::WebNode& node) {
+                               const blink::WebNode& node,
+                               const bool use_system_specific_flow) {
   // If still not finished with earlier print request simply ignore.
-  if (prep_frame_view_)
+  DLOG(INFO) << "DGN Print";
+
+  if (prep_frame_view_) {
+    DLOG(INFO) << "DGN Print request ignored";
     return;
+  }
 
   FrameReference frame_ref(frame);
 
@@ -1288,6 +1298,8 @@ void PrintWebViewHelper::Print(blink::WebLocalFrame* frame,
     return;  // Failed to init print page settings.
   }
 
+  DLOG(INFO) << "DGN CalculateNumberOfPages OK";
+
   // Some full screen plugins can say they don't want to print.
   if (!expected_page_count) {
     DidFinishPrinting(FAIL_PRINT);
@@ -1296,11 +1308,14 @@ void PrintWebViewHelper::Print(blink::WebLocalFrame* frame,
 
   // Ask the browser to show UI to retrieve the final print settings.
   if (!GetPrintSettingsFromUser(frame_ref.GetFrame(), node,
-                                expected_page_count)) {
+                                expected_page_count,
+                                use_system_specific_flow)) {
     DidFinishPrinting(OK);  // Release resources and fail silently.
     return;
   }
 
+  DLOG(INFO) << "DGN GetPrintSettingsFromUser OK";
+
   // Render Pages for printing.
   if (!RenderPagesForPrint(frame_ref.GetFrame(), node)) {
     LOG(ERROR) << "RenderPagesForPrint failed";
@@ -1573,7 +1588,8 @@ bool PrintWebViewHelper::UpdatePrintSettings(
 
 bool PrintWebViewHelper::GetPrintSettingsFromUser(blink::WebFrame* frame,
                                                   const blink::WebNode& node,
-                                                  int expected_pages_count) {
+                                                  int expected_pages_count,
+                                                  const bool system_specific) {
   PrintHostMsg_ScriptedPrint_Params params;
   PrintMsg_PrintPages_Params print_settings;
 
@@ -1584,6 +1600,7 @@ bool PrintWebViewHelper::GetPrintSettingsFromUser(blink::WebFrame* frame,
   if (PrintingNodeOrPdfFrame(frame, node))
     margin_type = GetMarginsForPdf(frame, node);
   params.margin_type = margin_type;
+  params.use_system_specific_flow = system_specific;
 
   Send(new PrintHostMsg_DidShowPrintDialog(routing_id()));