Fix a crash related to detaching a frame embedding pepper plugin with selection

third_party/WebKit/Source/web/WebFrameWidgetImpl.cpp

Index: third_party/WebKit/Source/web/WebFrameWidgetImpl.cpp
diff --git a/third_party/WebKit/Source/web/WebFrameWidgetImpl.cpp b/third_party/WebKit/Source/web/WebFrameWidgetImpl.cpp
index 76d4b0beec8e11c5bccccaa769bebd331ab89ab3..913e58bd61bc3f4f743cd7e7184037b7a1e71d2d 100644
--- a/third_party/WebKit/Source/web/WebFrameWidgetImpl.cpp
+++ b/third_party/WebKit/Source/web/WebFrameWidgetImpl.cpp
@@ -596,6 +596,10 @@ bool WebFrameWidgetImpl::SelectionBounds(WebRect& anchor,
   if (!local_frame)
     return false;
 
+  FrameSelection& selection = local_frame->Selection();
+  if (!selection.IsAvailable() || selection.GetSelectionInDOMTree().IsNone())
+    return false;
+
   // TODO(editing-dev): The use of updateStyleAndLayoutIgnorePendingStylesheets
   // needs to be audited.  See http://crbug.com/590369 for more details.
   local_frame->GetDocument()->UpdateStyleAndLayoutIgnorePendingStylesheets();
@@ -603,7 +607,6 @@ bool WebFrameWidgetImpl::SelectionBounds(WebRect& anchor,
   DocumentLifecycle::DisallowTransitionScope disallow_transition(
       local_frame->GetDocument()->Lifecycle());
 
-  FrameSelection& selection = local_frame->Selection();
   if (selection.ComputeVisibleSelectionInDOMTree().IsNone())
     return false;
 
@@ -642,11 +645,14 @@ bool WebFrameWidgetImpl::SelectionTextDirection(WebTextDirection& start,
   if (!frame)
     return false;
 
+  FrameSelection& selection = frame->Selection();
+  if (!selection.IsAvailable())
+    return false;
+
   // TODO(editing-dev): The use of updateStyleAndLayoutIgnorePendingStylesheets
   // needs to be audited.  See http://crbug.com/590369 for more details.
   frame->GetDocument()->UpdateStyleAndLayoutIgnorePendingStylesheets();
 
-  FrameSelection& selection = frame->Selection();
   if (selection.ComputeVisibleSelectionInDOMTree()
           .ToNormalizedEphemeralRange()
           .IsNull())
@@ -662,9 +668,9 @@ bool WebFrameWidgetImpl::SelectionTextDirection(WebTextDirection& start,
 // code needs to be refactored  (http://crbug.com/629721).
 bool WebFrameWidgetImpl::IsSelectionAnchorFirst() const {
   if (const LocalFrame* frame = FocusedLocalFrameInWidget()) {
-    return frame->Selection()
-        .ComputeVisibleSelectionInDOMTreeDeprecated()
-        .IsBaseFirst();
+    FrameSelection& selection = frame->Selection();
+    return selection.IsAvailable() &&
+           selection.ComputeVisibleSelectionInDOMTreeDeprecated().IsBaseFirst();
   }
   return false;
 }