Add more logging to debug DumpAccessibilityEvent* test failures

content/browser/accessibility/browser_accessibility_manager_win.cc

Index: content/browser/accessibility/browser_accessibility_manager_win.cc
diff --git a/content/browser/accessibility/browser_accessibility_manager_win.cc b/content/browser/accessibility/browser_accessibility_manager_win.cc
index 698f0190d22ce5fd700e3de92e71e435985be788..f62c7c157f9479bd6e15628ed25eaf36c6337bbb 100644
--- a/content/browser/accessibility/browser_accessibility_manager_win.cc
+++ b/content/browser/accessibility/browser_accessibility_manager_win.cc
@@ -76,12 +76,19 @@ IAccessible* BrowserAccessibilityManagerWin::GetParentIAccessible() {
 void BrowserAccessibilityManagerWin::MaybeCallNotifyWinEvent(DWORD event,
                                                              LONG child_id) {
   BrowserAccessibilityDelegate* delegate = GetDelegateFromRootManager();
-  if (!delegate)
+  if (!delegate) {
+    // This line and other LOG(WARNING) lines are temporary, to debug
+    // flaky failures in DumpAccessibilityEvent* tests.
+    // http://crbug.com/440579
+    LOG(WARNING) << "Not firing AX event because of no delegate";
     return;
+  }
 
   HWND hwnd = delegate->AccessibilityGetAcceleratedWidget();
-  if (!hwnd)
+  if (!hwnd) {
+    LOG(WARNING) << "Not firing AX event because of no hwnd";
     return;
+  }
 
   ::NotifyWinEvent(event, hwnd, OBJID_CLIENT, child_id);
 }
@@ -130,8 +137,10 @@ void BrowserAccessibilityManagerWin::NotifyAccessibilityEvent(
     ui::AXEvent event_type,
     BrowserAccessibility* node) {
   BrowserAccessibilityDelegate* root_delegate = GetDelegateFromRootManager();
-  if (!root_delegate || !root_delegate->AccessibilityGetAcceleratedWidget())
+  if (!root_delegate || !root_delegate->AccessibilityGetAcceleratedWidget()) {
+    LOG(WARNING) << "Not firing AX event because of no root_delegate or hwnd";
     return;
+  }
 
   // Inline text boxes are an internal implementation detail, we don't
   // expose them to Windows.