PDF: Selection Invalidation should compensate for rounding errors.

pdf/pdfium/pdfium_engine.cc

Index: pdf/pdfium/pdfium_engine.cc
diff --git a/pdf/pdfium/pdfium_engine.cc b/pdf/pdfium/pdfium_engine.cc
index 8a12c36f5109e5682128ddad48af8418d3240e55..e96f88ac5ebbcf8da89be7b47ef128d7e4cb948a 100644
--- a/pdf/pdfium/pdfium_engine.cc
+++ b/pdf/pdfium/pdfium_engine.cc
@@ -3291,13 +3291,13 @@ PDFiumEngine::SelectionChangeInvalidator::~SelectionChangeInvalidator() {
   bool selection_changed = false;
   for (const auto& old_selection : old_selections_) {
     if (!old_selection.IsEmpty()) {
-      engine_->client_->Invalidate(old_selection);
+      Invalidate(old_selection);
       selection_changed = true;
     }
   }
   for (const auto& new_selection : new_selections) {
     if (!new_selection.IsEmpty()) {
-      engine_->client_->Invalidate(new_selection);
+      Invalidate(new_selection);
       selection_changed = true;
     }
   }
@@ -3321,6 +3321,13 @@ PDFiumEngine::SelectionChangeInvalidator::GetVisibleSelections() const {
   return rects;
 }
 
+void PDFiumEngine::SelectionChangeInvalidator::Invalidate(
+    const pp::Rect& selection) {
+  pp::Rect expanded_selection = selection;
+  expanded_selection.Inset(-1, -1);
+  engine_->client_->Invalidate(expanded_selection);
+}
+
 PDFiumEngine::MouseDownState::MouseDownState(
     const PDFiumPage::Area& area,
     const PDFiumPage::LinkTarget& target)