Bug 629878 - Part 2: Do not scroll the selection into view when restoring the selection offsets for a text control after a reframe; r=roc a=blocking-final+

Previously, we used to scroll the text control's selection into view after a
reframe.  This had two problems: it was not precise (in case the selection was
modified by the mouse, for example), and it lead to problems such as bug 629878
if the control's frame was reconstructed because of the control being moved
inside the DOM.

This patch disables that behavior by wrapping the selection scroll function
into nsITextControlFrame::ScrollSelectionIntoView, so that APIs such as
setSelectionRange on the text control's content node can still call it
explicitly (since they actually need this behavior), but other callers of
nsITextControlFrame::SetSelectionRange (such as the nsTextEditorState
object's selection offset restoring mechanism) don't get this behavior as
an undesired side-effect.

content/html/content/src/nsHTMLInputElement.cpp

@@ -2857,8 +2857,12 @@ nsHTMLInputElement::SetSelectionRange(PRInt32 aSelectionStart,
 
   if (formControlFrame) {
     nsITextControlFrame* textControlFrame = do_QueryFrame(formControlFrame);
-    if (textControlFrame)
+    if (textControlFrame) {
       rv = textControlFrame->SetSelectionRange(aSelectionStart, aSelectionEnd);
+      if (NS_SUCCEEDED(rv)) {
+        rv = textControlFrame->ScrollSelectionIntoView();
+      }
+    }
   }
 
   return rv;
@@ -2881,8 +2885,12 @@ nsHTMLInputElement::SetSelectionStart(PRInt32 aSelectionStart)
 
   if (formControlFrame) {
     nsITextControlFrame* textControlFrame = do_QueryFrame(formControlFrame);
-    if (textControlFrame)
+    if (textControlFrame) {
       rv = textControlFrame->SetSelectionStart(aSelectionStart);
+      if (NS_SUCCEEDED(rv)) {
+        rv = textControlFrame->ScrollSelectionIntoView();
+      }
+    }
   }
 
   return rv;
@@ -2906,8 +2914,12 @@ nsHTMLInputElement::SetSelectionEnd(PRInt32 aSelectionEnd)
 
   if (formControlFrame) {
     nsITextControlFrame* textControlFrame = do_QueryFrame(formControlFrame);
-    if (textControlFrame)
+    if (textControlFrame) {
       rv = textControlFrame->SetSelectionEnd(aSelectionEnd);
+      if (NS_SUCCEEDED(rv)) {
+        rv = textControlFrame->ScrollSelectionIntoView();
+      }
+    }
   }
 
   return rv;

content/html/content/src/nsHTMLTextAreaElement.cpp

@@ -879,8 +879,12 @@ nsHTMLTextAreaElement::SetSelectionStart(PRInt32 aSelectionStart)
 
   if (formControlFrame){
     nsITextControlFrame* textControlFrame = do_QueryFrame(formControlFrame);
-    if (textControlFrame)
+    if (textControlFrame) {
       rv = textControlFrame->SetSelectionStart(aSelectionStart);
+      if (NS_SUCCEEDED(rv)) {
+        rv = textControlFrame->ScrollSelectionIntoView();
+      }
+    }
   }
 
   return rv;
@@ -903,8 +907,12 @@ nsHTMLTextAreaElement::SetSelectionEnd(PRInt32 aSelectionEnd)
 
   if (formControlFrame) {
     nsITextControlFrame* textControlFrame = do_QueryFrame(formControlFrame);
-    if (textControlFrame)
+    if (textControlFrame) {
       rv = textControlFrame->SetSelectionEnd(aSelectionEnd);
+      if (NS_SUCCEEDED(rv)) {
+        rv = textControlFrame->ScrollSelectionIntoView();
+      }
+    }
   }
 
   return rv;
@@ -934,8 +942,12 @@ nsHTMLTextAreaElement::SetSelectionRange(PRInt32 aSelectionStart, PRInt32 aSelec
 
   if (formControlFrame) {
     nsITextControlFrame* textControlFrame = do_QueryFrame(formControlFrame);
-    if (textControlFrame)
+    if (textControlFrame) {
       rv = textControlFrame->SetSelectionRange(aSelectionStart, aSelectionEnd);
+      if (NS_SUCCEEDED(rv)) {
+        rv = textControlFrame->ScrollSelectionIntoView();
+      }
+    }
   }
 
   return rv;

layout/forms/nsITextControlFrame.h

@@ -76,6 +76,8 @@ public:
    * @throws various and sundry other things
    */
   virtual nsresult EnsureEditorInitialized() = 0;
+
+  virtual nsresult ScrollSelectionIntoView() = 0;
 };
 
 #endif

layout/forms/nsTextControlFrame.cpp

@@ -855,18 +855,23 @@ nsTextControlFrame::SetSelectionInternal(nsIDOMNode *aStartNode,
   NS_ENSURE_SUCCESS(rv, rv);
 
   rv = selection->AddRange(range);  // NOTE: can destroy the world
-  NS_ENSURE_SUCCESS(rv, rv);
+  return rv;
+}
 
-  // Fetch it again since it might have been destroyed (bug 626014).
-  selCon = txtCtrl->GetSelectionController();
-  if (!selCon) {
-    return NS_OK;  // nothing to scroll, we're done
+nsresult
+nsTextControlFrame::ScrollSelectionIntoView()
+{
+  nsCOMPtr<nsITextControlElement> txtCtrl = do_QueryInterface(GetContent());
+  NS_ASSERTION(txtCtrl, "Content not a text control element");
+  nsISelectionController* selCon = txtCtrl->GetSelectionController();
+  if (selCon) {
+    // Scroll the selection into view (see bug 231389).
+    return selCon->ScrollSelectionIntoView(nsISelectionController::SELECTION_NORMAL,
+                                           nsISelectionController::SELECTION_FOCUS_REGION,
+                                           nsISelectionController::SCROLL_FIRST_ANCESTOR_ONLY);
   }
 
-  // Scroll the selection into view (see bug 231389).
-  return selCon->ScrollSelectionIntoView(nsISelectionController::SELECTION_NORMAL,
-                                         nsISelectionController::SELECTION_FOCUS_REGION,
-                                         nsISelectionController::SCROLL_FIRST_ANCESTOR_ONLY);
+  return NS_ERROR_FAILURE;
 }
 
 nsresult
@@ -914,8 +919,11 @@ nsTextControlFrame::SelectAllOrCollapseToEndOfText(PRBool aSelect)
     }
   }
 
-  return SetSelectionInternal(rootNode, aSelect ? 0 : numChildren,
-                              rootNode, numChildren);
+  rv = SetSelectionInternal(rootNode, aSelect ? 0 : numChildren,
+                            rootNode, numChildren);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return ScrollSelectionIntoView();
 }
 
 nsresult

layout/forms/nsTextControlFrame.h

@@ -370,6 +370,8 @@ protected:
   nsresult CalcIntrinsicSize(nsIRenderingContext* aRenderingContext,
                              nsSize&              aIntrinsicSize);
 
+  nsresult ScrollSelectionIntoView();
+
 private:
   //helper methods
   nsresult SetSelectionInternal(nsIDOMNode *aStartNode, PRInt32 aStartOffset,