Win Native Notifications: Fix crash when GetNamedItem returns null.

Bug: 881109, 734095
Change-Id: Ic530a30c653c202c279bf4074022a122cfcba2ac
Reviewed-on: https://chromium-review.googlesource.com/1209485
Commit-Queue: Finnur Thorarinsson <finnur@chromium.org>
Commit-Queue: Peter Beverloo <peter@chromium.org>
Reviewed-by: Peter Beverloo <peter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#589144}

chrome/browser/notifications/win/notification_metrics.h

@@ -88,6 +88,8 @@ enum class GetNotificationLaunchIdStatus {
   GET_NODE_VALUE_FAILED = 8,
   CONVERSION_TO_PROP_VALUE_FAILED = 9,
   GET_STRING_FAILED = 10,
+  GET_NAMED_ITEM_NULL = 11,
+  GET_FIRST_CHILD_NULL = 12,
   COUNT  // Must be the final value.
 };
 

chrome/browser/notifications/win/notification_util.cc

@@ -77,6 +77,13 @@ NotificationLaunchId GetNotificationLaunchId(
     return NotificationLaunchId();
   }
 
+  if (!leaf) {
+    LogGetNotificationLaunchIdStatus(
+        GetNotificationLaunchIdStatus::GET_NAMED_ITEM_NULL);
+    DLOG(ERROR) << "GetNamedItem returned null querying for 'launch' attribute";
+    return NotificationLaunchId();
+  }
+
   mswr::ComPtr<winxml::Dom::IXmlNode> child;
   hr = leaf->get_FirstChild(&child);
   if (FAILED(hr)) {
@@ -86,6 +93,13 @@ NotificationLaunchId GetNotificationLaunchId(
     return NotificationLaunchId();
   }
 
+  if (!child) {
+    LogGetNotificationLaunchIdStatus(
+        GetNotificationLaunchIdStatus::GET_FIRST_CHILD_NULL);
+    DLOG(ERROR) << "Launch attribute is a null node";
+    return NotificationLaunchId();
+  }
+
   mswr::ComPtr<IInspectable> inspectable;
   hr = child->get_NodeValue(&inspectable);
   if (FAILED(hr)) {

tools/metrics/histograms/enums.xml

@@ -51627,6 +51627,8 @@ Full version information for the fingerprint enum values:
   <int value="8" label="GET_NODE_VALUE_FAILED"/>
   <int value="9" label="CONVERSION_TO_PROP_VALUE_FAILED"/>
   <int value="10" label="GET_STRING_FAILED"/>
+  <int value="11" label="GET_NAMED_ITEM_NULL"/>
+  <int value="12" label="GET_FIRST_CHILD_NULL"/>
 </enum>
 
 <enum name="WindowsNotificationGetSettingPolicy">