Bug 1302470 Part 3: Branch IsRangeVisible to delegate to IsRangeRendered when range is in viewport. r=masayuki

MozReview-Commit-ID: LZyvt08I9vz

--HG--
extra : rebase_source : 56f44a967a3647a3c6bc326232467eaf69b7f447

toolkit/components/typeaheadfind/nsTypeAheadFind.cpp

@@ -1210,22 +1210,22 @@ nsTypeAheadFind::IsRangeVisible(nsIPresShell *aPresShell,
     return false;
 
   nsIFrame *frame = content->GetPrimaryFrame();
-  if (!frame)    
+  if (!frame) {
     return false;  // No frame! Not visible then.
+  }
 
-  if (!frame->StyleVisibility()->IsVisible())
+  if (!frame->StyleVisibility()->IsVisible()) {
     return false;
+  }
 
   // Detect if we are _inside_ a text control, or something else with its own
   // selection controller.
   if (aUsesIndependentSelection) {
-    *aUsesIndependentSelection = 
+    *aUsesIndependentSelection =
       (frame->GetStateBits() & NS_FRAME_INDEPENDENT_SELECTION);
   }
 
   // ---- We have a frame ----
-  if (!aMustBeInViewPort)   
-    return true; //  Don't need it to be on screen, just in rendering tree
 
   // Get the next in flow frame that contains the range start
   int32_t startRangeOffset, startFrameOffset, endFrameOffset;
@@ -1259,12 +1259,22 @@ nsTypeAheadFind::IsRangeVisible(nsIPresShell *aPresShell,
                                     minDistance);
 
     if (rectVisibility != nsRectVisibility_kAboveViewport) {
-      return true;
+      // This is an early exit case, where we return true iff the range
+      // is actually rendered.
+      return IsRangeRendered(aPresShell, aPresContext, aRange);
     }
   }
 
-  // We know that the target range isn't usable because it's not in the
-  // view port. Move range forward to first visible point,
+  // Below this point, we know the range is not in the viewport.
+
+  if (!aMustBeInViewPort) {
+    // This is an early exit case because we don't care that that range
+    // is out of viewport, so we return that the range is "visible".
+    return true;
+  }
+
+  // The range isn't in the viewport, but we could scroll it into view.
+  // Move range forward to first visible point,
   // this speeds us up a lot in long documents
   nsCOMPtr<nsIFrameEnumerator> frameTraversal;
   nsCOMPtr<nsIFrameTraversal> trav(do_CreateInstance(kFrameTraversalCID));
@@ -1278,8 +1288,9 @@ nsTypeAheadFind::IsRangeVisible(nsIPresShell *aPresShell,
                             false  // aSkipPopupChecks
                             );
 
-  if (!frameTraversal)
+  if (!frameTraversal) {
     return false;
+  }
 
   while (rectVisibility == nsRectVisibility_kAboveViewport) {
     frameTraversal->Next();