Bug 1590185 Part 2 - Support paged mode layout in layout debugger. r=dbaron

This patch adds a menu item in "Toggle" -> "Paged Mode". If the item is
toggled, after finishing loading the document, the document will be
forced into paged mode.

The print settings in `nsLayoutDebuggingTools::SetPagedMode()` are
similar to `setupPrintMode()` in reftest-content.js.

Remove the hack in nsDocumentViewer::InitInternal() because we don't
want to set a new document when mIsPageMode = false.

Differential Revision: https://phabricator.services.mozilla.com/D49993

--HG--
extra : moz-landing-system : lando

layout/base/nsDocumentViewer.cpp

@@ -875,12 +875,6 @@ nsresult nsDocumentViewer::InitInternal(
     nsIWidget* aParentWidget, nsISupports* aState, WindowGlobalChild* aActor,
     const nsIntRect& aBounds, bool aDoCreation, bool aNeedMakeCX /*= true*/,
     bool aForceSetNewDocument /* = true*/) {
-  if (mIsPageMode) {
-    // XXXbz should the InitInternal in SetPageModeForTesting just pass false
-    // here itself?
-    aForceSetNewDocument = false;
-  }
-
   // We don't want any scripts to run here. That can cause flushing,
   // which can cause reentry into initialization of this document viewer,
   // which would be disastrous.
@@ -4119,8 +4113,8 @@ NS_IMETHODIMP nsDocumentViewer::SetPageModeForTesting(
     nsresult rv = mPresContext->Init(mDeviceContext);
     NS_ENSURE_SUCCESS(rv, rv);
   }
-  NS_ENSURE_SUCCESS(
-      InitInternal(mParentWidget, nullptr, nullptr, mBounds, true, false),
+  NS_ENSURE_SUCCESS(InitInternal(mParentWidget, nullptr, nullptr, mBounds, true,
+                                 false, false),
                     NS_ERROR_FAILURE);
 
   Show();

layout/tools/layout-debug/src/nsILayoutDebuggingTools.idl

@@ -29,6 +29,7 @@ interface nsILayoutDebuggingTools : nsISupports
     void setVisualDebugging(in boolean enabled);
     void setVisualEventDebugging(in boolean enabled);
     void setReflowCounts(in boolean enabled);
+    void setPagedMode(in boolean enabled);
 
     /* Run various tests. */
     void dumpWebShells();

layout/tools/layout-debug/src/nsLayoutDebuggingTools.cpp

@@ -9,6 +9,8 @@
 #include "nsIDocShell.h"
 #include "nsPIDOMWindow.h"
 #include "nsIContentViewer.h"
+#include "nsIPrintSettings.h"
+#include "nsIPrintSettingsService.h"
 
 #include "nsIServiceManager.h"
 #include "nsAtom.h"
@@ -115,6 +117,38 @@ nsLayoutDebuggingTools::SetReflowCounts(bool aShow) {
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsLayoutDebuggingTools::SetPagedMode(bool aPagedMode) {
+  nsCOMPtr<nsIPrintSettingsService> printSettingsService =
+      do_GetService("@mozilla.org/gfx/printsettings-service;1");
+  nsCOMPtr<nsIPrintSettings> printSettings;
+
+  printSettingsService->GetNewPrintSettings(getter_AddRefs(printSettings));
+
+  // The setup is the similar as setupPrintMode() in reftest-content.js except
+  // we set the paper size by using US letter size 8.5 x 11 inches, so the page
+  // area is larger and easier read when debugging real web pages.
+  printSettings->SetPaperWidth(8.5);
+  printSettings->SetPaperHeight(11);
+
+  nsIntMargin unwriteableMargin(0, 0, 0, 0);
+  printSettings->SetUnwriteableMarginInTwips(unwriteableMargin);
+
+  printSettings->SetHeaderStrLeft(NS_LITERAL_STRING(""));
+  printSettings->SetHeaderStrCenter(NS_LITERAL_STRING(""));
+  printSettings->SetHeaderStrRight(NS_LITERAL_STRING(""));
+
+  printSettings->SetFooterStrLeft(NS_LITERAL_STRING(""));
+  printSettings->SetFooterStrCenter(NS_LITERAL_STRING(""));
+  printSettings->SetFooterStrRight(NS_LITERAL_STRING(""));
+
+  nsCOMPtr<nsIContentViewer> contentViewer(doc_viewer(mDocShell));
+  contentViewer->SetPageModeForTesting(aPagedMode, printSettings);
+
+  ForceRefresh();
+  return NS_OK;
+}
+
 static void DumpAWebShell(nsIDocShellTreeItem* aShellItem, FILE* out,
                           int32_t aIndent) {
   nsString name;

layout/tools/layout-debug/ui/content/layoutdebug.js

@@ -50,6 +50,7 @@ class Debugger {
     this._flags = new Map();
     this._visualDebugging = false;
     this._visualEventDebugging = false;
+    this._pagedMode = false;
     this._attached = false;
 
     for (let [name, pref] of Object.entries(FEATURES)) {
@@ -112,6 +113,20 @@ class Debugger {
     this._sendMessage("setVisualEventDebugging", v);
   }
 
+  get pagedMode() {
+    return this._pagedMode;
+  }
+
+  set pagedMode(v) {
+    v = !!v;
+    this._pagedMode = v;
+    this.setPagedMode(this._pagedMode);
+  }
+
+  setPagedMode(v) {
+    this._sendMessage("setPagedMode", v);
+  }
+
   _sendMessage(name, arg) {
     gBrowser.messageManager.sendAsyncMessage("LayoutDebug:Call", { name, arg });
   }
@@ -201,6 +216,11 @@ nsLDBBrowserContentListener.prototype = {
       this.mStatusText.value = gURLBar.value + " loaded";
       this.mLoading = false;
 
+      if (gDebugger.pagedMode) {
+        // Change to paged mode after the page is loaded.
+        gDebugger.setPagedMode(true);
+      }
+
       if (gBrowser.currentURI.spec != "about:blank") {
         // We check for about:blank just to avoid one or two STATE_STOP
         // notifications that occur before the loadURI() call completes.

layout/tools/layout-debug/ui/content/layoutdebug.xul

@@ -76,6 +76,7 @@
             <menuitem type="checkbox" id="menu_crossingEventDumping" label="&ldb.crossingEventDumping.label;" accesskey="&ldb.crossingEventDumping.accesskey;" oncommand="toggle(this);" />
             <menuseparator />
             <menuitem type="checkbox" id="menu_reflowCounts" label="&ldb.reflowCounts.label;" accesskey="&ldb.reflowCounts.accesskey;" oncommand="toggle(this);" />
+            <menuitem type="checkbox" id="menu_pagedMode" label="&ldb.pagedMode.label;" accesskey="&ldb.pagedMode.accesskey;" oncommand="toggle(this);" />
           </menupopup>
         </menu>
         <menu label="&ldb.DumpMenu.label;"

layout/tools/layout-debug/ui/locale/en-US/layoutdebug.dtd

@@ -33,6 +33,8 @@
 <!ENTITY ldb.crossingEventDumping.accesskey "C">
 <!ENTITY ldb.reflowCounts.label "Reflow Counts">
 <!ENTITY ldb.reflowCounts.accesskey "R">
+<!ENTITY ldb.pagedMode.label "Paged Mode">
+<!ENTITY ldb.pagedMode.accesskey "G">
 
 <!ENTITY ldb.DumpMenu.label "Dump">
 <!ENTITY ldb.DumpMenu.accesskey "D">