Add a "Simplify Page" option to the print preview dialog

chrome/browser/ui/webui/print_preview/print_preview_handler.cc

Index: chrome/browser/ui/webui/print_preview/print_preview_handler.cc
diff --git a/chrome/browser/ui/webui/print_preview/print_preview_handler.cc b/chrome/browser/ui/webui/print_preview/print_preview_handler.cc
index 237bba967a6013be8075d1ae87087d520386b79e..eb42f2507ed7b6fe6f67cc762389ad6269fd8f1e 100644
--- a/chrome/browser/ui/webui/print_preview/print_preview_handler.cc
+++ b/chrome/browser/ui/webui/print_preview/print_preview_handler.cc
@@ -30,6 +30,7 @@
 #include "base/values.h"
 #include "chrome/browser/app_mode/app_mode_utils.h"
 #include "chrome/browser/browser_process.h"
+#include "chrome/browser/dom_distiller/tab_utils.h"
 #include "chrome/browser/platform_util.h"
 #include "chrome/browser/printing/print_dialog_cloud.h"
 #include "chrome/browser/printing/print_error_dialog.h"
@@ -57,6 +58,7 @@
 #include "components/cloud_devices/common/cloud_device_description.h"
 #include "components/cloud_devices/common/cloud_devices_urls.h"
 #include "components/cloud_devices/common/printer_description.h"
+#include "components/dom_distiller/core/url_utils.h"
 #include "components/printing/common/print_messages.h"
 #include "components/signin/core/browser/gaia_cookie_manager_service.h"
 #include "components/signin/core/browser/profile_oauth2_token_service.h"
@@ -165,6 +167,8 @@ const char kHidePrintWithSystemDialogLink[] = "hidePrintWithSystemDialogLink";
 #endif
 // Name of a dictionary field holding the state of selection for document.
 const char kDocumentHasSelection[] = "documentHasSelection";
+// Dictionary field indicating whether to simplify the page.
+const char kPrintFriendlyEnabled[] = "printFriendlyEnabled";
 
 // Id of the predefined PDF printer.
 const char kLocalPdfPrinterId[] = "Save as PDF";
@@ -823,8 +827,24 @@ void PrintPreviewHandler::HandleGetPreview(const base::ListValue* args) {
   }
 
   VLOG(1) << "Print preview request start";
-  RenderViewHost* rvh = initiator->GetRenderViewHost();
-  rvh->Send(new PrintMsg_PrintPreview(rvh->GetRoutingID(), *settings));
+
+  bool print_friendly = false;
+  if (!settings->GetBoolean(printing::kSettingPrintFriendlyEnabled,
+                            &print_friendly)) {
+    NOTREACHED();
+  }
+
+  if (print_friendly) {
+    if (!hidden_print_preview_)
+      MaybeStartDistillation(initiator);

[nyquist, 2015/05/13 07:56:38]

Could this be simplified by using the new DistillAndView from
https://codereview.chromium.org/1058193002/ ?

Depending on how we deal with the @media print things, it might have to change a
little bit though to use the correct URL.

[arjunpatel, 2015/05/27 00:16:45]

Yes, depending on whether or not we keep the synchronous DOM Distiller UI, this
can use DistillAndView.

+
+      hidden_print_preview_.reset(
+        new HiddenPrintPreview(initiator, print_preview_ui()));
+      hidden_print_preview_->SetSettings(settings.Pass());
+  } else {
+    RenderViewHost* rvh = initiator->GetRenderViewHost();
+    rvh->Send(new PrintMsg_PrintPreview(rvh->GetRoutingID(), *settings));
+  }
 }
 
 void PrintPreviewHandler::HandlePrint(const base::ListValue* args) {
@@ -1237,6 +1257,15 @@ void PrintPreviewHandler::SendInitialSettings(
   initial_settings.SetBoolean(kHidePrintWithSystemDialogLink, is_ash);
 #endif
 
+  WebContents* initiator = GetInitiator();
+  bool can_simplify = false;
+  if (initiator) {
+      can_simplify = cmdline->HasSwitch(switches::kEnableDomDistiller) &&

[nyquist, 2015/05/13 07:56:38]

Should this also check to see if we assume that the distillation will work?
See dom_distiller::IsDistillablePage (
https://code.google.com/p/chromium/codesearch#chromium/src/components/dom_dis...
)

[arjunpatel, 2015/05/27 17:10:11]

The latest version of the CL does this, showing the checkbox asynchronously as
the dialog appears. It seems like many pages are not marked as distillable even
using the AdaBoost algorithm, but we've been testing with the alwaystrue
heuristic.

+         dom_distiller::url_utils::IsUrlDistillable(
+            initiator->GetLastCommittedURL());
+    }
+  initial_settings.SetBoolean(kPrintFriendlyEnabled, can_simplify);
+
   if (print_preview_ui()->source_is_modifiable())
     GetNumberFormatAndMeasurementSystem(&initial_settings);
   web_ui()->CallJavascriptFunction("setInitialSettings", initial_settings);