Explicitly check for null parent in CXFA_LayoutPageMgr::CreateViewRecord()

Prior to the refactoring in 112b16f, this would silently succeed
despite invoking a method on a null |this| because of an early
return prior to touching member variables. This restores that
old behaviour.

Bug: pdfium:1301
Change-Id: I3fdb37cd1420b5af86d784d24fd6e15a010bb224
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/54710
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
diff --git a/testing/resources/bug_1301.in b/testing/resources/bug_1301.in
new file mode 100644
index 0000000..21c68cb
--- /dev/null
+++ b/testing/resources/bug_1301.in
@@ -0,0 +1,33 @@
+{{header}}
+{{include xfa_catalog_1_0.fragment}}
+{{include xfa_object_2_0.fragment}}
+{{include xfa_preamble_3_0.fragment}}
+{{include xfa_config_4_0.fragment}}
+{{object 5 0}} <<
+  {{streamlen}}
+>>
+stream
+<template xmlns="http://www.xfa.org/schema/xfa-template/3.0/">
+  <subform name="Form01" layout="tb" locale="en_ZA" restoreState="auto">
+    <pageSet>
+      <pageArea name="Page1" id="Page1" initialNumber="1">
+        <contentArea x="10.455mm" w="190.5mm" h="286mm"/>
+        <occur min="1" max="1"/>
+      </pageArea>
+    </pageSet>
+    <subform w="190.5mm" h="286mm" name="TForm1SubForm1">
+    </subform>
+    <subform w="190.5mm" h="286mm">
+      <breakBefore targetType="pageArea" startNew="1"/>
+    </subform>
+  </subform>
+</template>
+endstream
+endobj
+{{include xfa_locale_6_0.fragment}}
+{{include xfa_postamble_7_0.fragment}}
+{{include xfa_pages_8_0.fragment}}
+{{xref}}
+{{trailer}}
+{{endxref}}
+%%EOF
diff --git a/testing/resources/bug_1301.pdf b/testing/resources/bug_1301.pdf
new file mode 100644
index 0000000..285c7f7
--- /dev/null
+++ b/testing/resources/bug_1301.pdf
@@ -0,0 +1,241 @@
+%PDF-1.7
+% ò¤ô
+1 0 obj <<
+  /AcroForm 2 0 R
+  /Extensions <<
+    /ADBE <<
+      /BaseVersion /1.7
+      /ExtensionLevel 8
+    >>
+  >>
+  /NeedsRendering true
+  /Pages 8 0 R
+  /Type /Catalog
+>>
+endobj
+2 0 obj <<
+  /XFA [
+    (preamble)
+    3 0 R
+    (config)
+    4 0 R
+    (template)
+    5 0 R
+    (localeSet)
+    6 0 R
+    (postamble)
+    7 0 R
+  ]
+>>
+endobj
+3 0 obj <<
+  /Length 124
+>>
+stream
+<xdp:xdp xmlns:xdp="http://ns.adobe.com/xdp/" timeStamp="2018-02-23T21:37:11Z" uuid="21482798-7bf0-40a4-bc5d-3cefdccf32b5">
+endstream
+endobj
+4 0 obj <<
+  /Length 642
+>>
+stream
+<config xmlns="http://www.xfa.org/schema/xci/3.0/">
+<agent name="designer">
+  <destination>pdf</destination>
+  <pdf>
+    <fontInfo/>
+  </pdf>
+</agent>
+<present>
+  <pdf>
+    <version>1.7</version>
+    <adobeExtensionLevel>8</adobeExtensionLevel>
+    <renderPolicy>client</renderPolicy>
+    <scriptModel>XFA</scriptModel>
+    <interactive>1</interactive>
+  </pdf>
+  <xdp>
+    <packets>*</packets>
+  </xdp>
+  <destination>pdf</destination>
+  <script>
+    <runScripts>server</runScripts>
+  </script>
+</present>
+<acrobat>
+  <acrobat7>
+    <dynamicRender>required</dynamicRender>
+  </acrobat7>
+  <validate>preSubmit</validate>
+</acrobat>
+</config>
+endstream
+endobj
+5 0 obj <<
+  /Length 538
+>>
+stream
+<template xmlns="http://www.xfa.org/schema/xfa-template/3.0/">
+  <subform name="Form01" layout="tb" locale="en_ZA" restoreState="auto">
+    <pageSet>
+      <pageArea name="Page1" id="Page1" initialNumber="1">
+        <contentArea x="10.455mm" w="190.5mm" h="286mm"/>
+        <occur min="1" max="1"/>
+      </pageArea>
+    </pageSet>
+    <subform w="190.5mm" h="286mm" name="TForm1SubForm1">
+    </subform>
+    <subform w="190.5mm" h="286mm">
+      <breakBefore targetType="pageArea" startNew="1"/>
+    </subform>
+  </subform>
+</template>
+endstream
+endobj
+6 0 obj <<
+  /Length 3455
+>>
+stream
+<localeSet xmlns="http://www.xfa.org/schema/xfa-locale-set/2.7/">
+  <locale name="en_US" desc="English (United States)">
+    <calendarSymbols name="gregorian">
+      <monthNames>
+        <month>January</month>
+        <month>February</month>
+        <month>March</month>
+        <month>April</month>
+        <month>May</month>
+        <month>June</month>
+        <month>July</month>
+        <month>August</month>
+        <month>September</month>
+        <month>October</month>
+        <month>November</month>
+        <month>December</month>
+      </monthNames>
+      <monthNames abbr="1">
+        <month>Jan</month>
+        <month>Feb</month>
+        <month>Mar</month>
+        <month>Apr</month>
+        <month>May</month>
+        <month>Jun</month>
+        <month>Jul</month>
+        <month>Aug</month>
+        <month>Sep</month>
+        <month>Oct</month>
+        <month>Nov</month>
+        <month>Dec</month>
+      </monthNames>
+      <dayNames>
+        <day>Sunday</day>
+        <day>Monday</day>
+        <day>Tuesday</day>
+        <day>Wednesday</day>
+        <day>Thursday</day>
+        <day>Friday</day>
+        <day>Saturday</day>
+      </dayNames>
+      <dayNames abbr="1">
+        <day>Sun</day>
+        <day>Mon</day>
+        <day>Tue</day>
+        <day>Wed</day>
+        <day>Thu</day>
+        <day>Fri</day>
+        <day>Sat</day>
+      </dayNames>
+      <meridiemNames>
+        <meridiem>AM</meridiem>
+        <meridiem>PM</meridiem>
+      </meridiemNames>
+      <eraNames>
+        <era>BC</era>
+        <era>AD</era>
+      </eraNames>
+    </calendarSymbols>
+    <datePatterns>
+      <datePattern name="full">EEEE, MMMM D, YYYY</datePattern>
+      <datePattern name="long">MMMM D, YYYY</datePattern>
+      <datePattern name="med">MMM D, YYYY</datePattern>
+      <datePattern name="short">M/D/YY</datePattern>
+    </datePatterns>
+    <timePatterns>
+      <timePattern name="full">h:MM:SS A Z</timePattern>
+      <timePattern name="long">h:MM:SS A Z</timePattern>
+      <timePattern name="med">h:MM:SS A</timePattern>
+      <timePattern name="short">h:MM A</timePattern>
+    </timePatterns>
+    <dateTimeSymbols>GyMdkHmsSEDFwWahKzZ</dateTimeSymbols>
+    <numberPatterns>
+      <numberPattern name="numeric">z,zz9.zzz</numberPattern>
+      <numberPattern name="currency">$z,zz9.99|($z,zz9.99)</numberPattern>
+      <numberPattern name="percent">z,zz9%</numberPattern>
+    </numberPatterns>
+    <numberSymbols>
+      <numberSymbol name="decimal">.</numberSymbol>
+      <numberSymbol name="grouping">,</numberSymbol>
+      <numberSymbol name="percent">%</numberSymbol>
+      <numberSymbol name="minus">-</numberSymbol>
+      <numberSymbol name="zero">0</numberSymbol>
+    </numberSymbols>
+    <currencySymbols>
+      <currencySymbol name="symbol">$</currencySymbol>
+      <currencySymbol name="isoname">USD</currencySymbol>
+      <currencySymbol name="decimal">.</currencySymbol>
+    </currencySymbols>
+    <typefaces>
+      <typeface name="Myriad Pro"/>
+      <typeface name="Minion Pro"/>
+      <typeface name="Courier Std"/>
+      <typeface name="Adobe Pi Std"/>
+      <typeface name="Adobe Hebrew"/>
+      <typeface name="Adobe Arabic"/>
+      <typeface name="Adobe Thai"/>
+      <typeface name="Kozuka Gothic Pro-VI M"/>
+      <typeface name="Kozuka Mincho Pro-VI R"/>
+      <typeface name="Adobe Ming Std L"/>
+      <typeface name="Adobe Song Std L"/>
+      <typeface name="Adobe Myungjo Std M"/>
+    </typefaces>
+  </locale>
+</localeSet>
+endstream
+endobj
+7 0 obj <<
+  /Length 11
+>>
+stream
+</xdp:xdp>
+endstream
+endobj
+8 0 obj <<
+  /Type /Pages
+  /Count 1
+  /Kids [9 0 R]
+>>
+endobj
+9 0 obj <<
+  /Type /Page
+  /Parent 2 0 R
+  /MediaBox [0 0 612 792]
+>>
+endobj
+xref
+0 10
+0000000000 65535 f 
+0000000015 00000 n 
+0000000199 00000 n 
+0000000358 00000 n 
+0000000534 00000 n 
+0000001228 00000 n 
+0000001818 00000 n 
+0000005326 00000 n 
+0000005388 00000 n 
+0000005451 00000 n 
+trailer <<
+  /Root 1 0 R
+  /Size 10
+>>
+{{endxref}}
+%%EOF
diff --git a/xfa/fxfa/layout/cxfa_layoutitem_embeddertest.cpp b/xfa/fxfa/layout/cxfa_layoutitem_embeddertest.cpp
index d98eea3..8a31402 100644
--- a/xfa/fxfa/layout/cxfa_layoutitem_embeddertest.cpp
+++ b/xfa/fxfa/layout/cxfa_layoutitem_embeddertest.cpp
@@ -12,11 +12,15 @@
 // Leaks. See https://crbug.com/pdfium/1265
 #define MAYBE_Bug_1265 DISABLED_Bug_1265
 
+// Leaks. See https://crbug.com/pdfium/1301
+#define MAYBE_Bug_1301 DISABLED_Bug_1301
+
 // Leaks. See https:://crbug.com/306123
 #define MAYBE_Bug_306123 DISABLED_Bug_306123
 
 #else
 #define MAYBE_Bug_1265 Bug_1265
+#define MAYBE_Bug_1301 Bug_1301
 #define MAYBE_Bug_306123 Bug_306123
 #endif
 
@@ -29,6 +33,18 @@
   UnloadPage(page0);
 }
 
+TEST_F(CXFALayoutItemEmbedderTest, MAYBE_Bug_1301) {
+  EXPECT_TRUE(OpenDocument("bug_1301.pdf"));
+  FPDF_PAGE page0 = LoadPage(0);
+  FPDF_PAGE page1 = LoadPage(1);
+  FPDF_PAGE page2 = LoadPage(2);
+  EXPECT_NE(nullptr, page0);
+  EXPECT_NE(nullptr, page1);
+  EXPECT_EQ(nullptr, page2);
+  UnloadPage(page0);
+  UnloadPage(page1);
+}
+
 TEST_F(CXFALayoutItemEmbedderTest, MAYBE_Bug_306123) {
   EXPECT_TRUE(OpenDocument("bug_306123.pdf"));
   FPDF_PAGE page0 = LoadPage(0);
diff --git a/xfa/fxfa/layout/cxfa_layoutpagemgr.cpp b/xfa/fxfa/layout/cxfa_layoutpagemgr.cpp
index 86bd0a9..67f85bb 100644
--- a/xfa/fxfa/layout/cxfa_layoutpagemgr.cpp
+++ b/xfa/fxfa/layout/cxfa_layoutpagemgr.cpp
@@ -636,7 +636,8 @@
     while (pPrePageSet->GetNextSibling()) {
       pPrePageSet = pPrePageSet->GetNextSibling()->AsViewLayoutItem();
     }
-    pPrePageSet->GetParent()->InsertAfter(pPageSetLayoutItem, pPrePageSet);
+    if (pPrePageSet->GetParent())
+      pPrePageSet->GetParent()->InsertAfter(pPageSetLayoutItem, pPrePageSet);
     m_pPageSetCurRoot = pPageSetLayoutItem;
   } else {
     pParentPageSetLayout->AppendLastChild(pPageSetLayoutItem);